iii. Stipe slender, sporangium

copper-colored 16. _C. cuprea_

1. CRIBRARIA ARGILLACEA _Pers._

PLATE XII., Figs. 12, 13; PLATE XVII., Fig. 1.

1791. _Stemonitis argillacea_ (Pers.) Gmel., _Syst. Nat._, II., 1469. 1796. _Cribraria argillacea_ Pers., _Obs. Myc._, I., p. 90.

Sporangia dull ochraceous-olivaceous, globose, nearly 1 mm. in diameter, sessile or short stipitate, closely gregarious or crowded, the peridial walls at maturity smooth, shining, except above, long persistent, obscurely reticulate, with irregular thickenings which at the apex at length present the appearance of an irregular, coarsely meshed net without nodal thickenings; stipe very short, stout, erect, reddish brown, spore-mass ochraceous, spores by transmitted light pale, spinulose, 5-6 mu.

This species stands just on the border-line between the tubiferas and the genus now before us. While on the one hand it possesses many characters such as the habit, form of sporangium, which are distinctly tubuline, on the other it shows in the upper peridial wall definite reticulations which suggest _Cribraria_. In freshly formed sporangia the reticulations are barely visible in the crown; later on they are more manifest, until, as spore-dispersal proceeds; the cribraria characters come out with sufficient distinctness, and in empty sporangia the reticulations may be seen to affect the entire peridial wall. The nodes are not expanded. The spores are pale by transmitted light, spinulose, about 6 mu. Plasmodium lead-colored. Found sometimes in large patches on rotten logs of various species. Not uncommon. Cf. _Lindbladia effusa_.

New England, New York, Pennsylvania, South Carolina, Ohio, Illinois, Iowa, Washington; Canada.

2. CRIBRARIA MACROCARPA _Schrader._

PLATE XVII., Fig. 2.

1797. _Cribraria macrocarpa_ Schrad., _Nov. Gen. Plant._, p. 8.

Sporangia more or less closely gregarious, yellowish brown, pear-shaped or obovate, large, .8-1 mm. in diameter, stipitate; stipe brown furrowed, erect or often nodding, about equal to the sporangium or longer; calyculus distinct, marked by numerous dark brown radiating ribs, iridescent, perforate above, deeply dentate, and merging gradually into the elegant network, of which the dark nodes are more distinctly expanded about half way up, less so at the apex and below, the filaments exceedingly delicate, simple, with occasional free ends projecting into the small meshes; spore-mass yellowish, spores by transmitted light almost colorless, minutely roughened, 5-6 mu.

Perhaps the most striking characteristic of the present species, aside from its large size, is the peculiarly perforated cup or calyculus. Schrader's artist failed him here completely. The structure is exceedingly delicate, the peridium between the ribs and reticulations reduced to the last degree of tenuity, with the iridescence of the soap-bubble, here and there lapsed entirely. Withal the structure seems firm enough and persists until all the spores are dissipated by the wind.

Easily distinguished from the preceding, its only rival in size, by the obovate or turbinate, netted sporangium, its much longer stem, and flat, perfectly formed nodes.

Rare. New York, North Carolina, South Carolina, Oregon; Toronto, Canada.

3. CRIBRARIA MINUTISSIMA _Schweinitz._

PLATE XVII., Figs. 6, 6 _a_.

1832. _Cribraria minutissima_ Schw., _N. A. F._, No. 2362.

Sporangia scattered, orange or nut-brown, very minute, .1-.3 mm. or less, globose or ellipsoidal, stipitate, erect or nodding; hypothallus none; stipe short, 1-3 times the sporangium, filiform, tapering upward, brown; the calyculus variable, sometimes well marked and separated from the net when fully mature, by a shallow constriction, more commonly small or entirely wanting, especially in the spherical sporangia; net simple, large meshed, without nodal expansions, the threads flattened; spore-mass yellow, spores by transmitted light, pale, nearly smooth, 5-6 mu.

A most beautiful tiny species. Generally in all the specimens before us, a perfect, spherical net, firm enough to retain its place and structure after all the spores have been scattered. When mature the spore-mass seems to roll about as a ball, freely within the net, the spores being thus gradually dispersed. The calyculus when present is without veins. _C. minima_ Berk. & C., and _C. microscopica_ Berk. & C. are doubtless the same thing. _Grev._, II., p. 67, 1823. See also _Bot. Gaz._, XIX., 397.

Rare. Pennsylvania, South Carolina, Missouri, Iowa; Black Hills, South Dakota.

4. CRIBRARIA RUFA (_Roth_) _Rost._

PLATE XIX., Fig. 8.

1788. _Stemonitis rufa_ Roth, _Fl. Germ._, I., p. 548. 1794. _Cribraria rufescens_ Pers., Roemer, _N. Mag. Bot._, I., p. 91. 1797. _Cribraria fulva_ Schrad., _Nov. Gen. Pl._, p. 5.

Sporangia scattered, sub-globose or turbinate, dark or reddish orange, .5-.7 mm. in diameter, erect, stipitate; stipe about equalling the height of the sporangium or longer, dark brown or black; calyculus one-third to one-half the sporangium, the margin toothed, the wall ribbed and continuous with the open wide-meshed net; the network deep yellow or orange, the threads flattened; the nodes not thickened, little differentiated; spores concolorous, by transmitted light, pale yellow, verruculose, 5-7 mu.

Similar to the preceding, but generally much larger and not so much inclined to brown. The size, however, is extremely variable in sporangia from the same plasmodium (reported white), some no larger than those of the species reckoned most minute.

Oregon. _Professor Morton Peck._

5. CRIBRARIA SPLENDENS (_Schrader_) _Rost._

PLATE XIX., Fig. 10.

1797. _Dictydium splendens_ Schrad., _Nov. Gen._, p. 14. 1801. _Cribraria splendens_ (Schrad.) Pers., _Syn. Fung._, p. 191.

Sporangia gregarious, globose, dusky yellow when filled with spores, dull or dusky brown when these are discharged, stipitate; stipe long, 3-4 times the sporangium, subulate, erect-nodding, brown; hypothallus none; network brown, with large meshes, imperfectly defined nodes and flattened threads; calyculus none, its place supplied by nine or ten distinct, firm ribs which radiate from the stipe and support the net, branching to blend with its reticulations; spore-mass yellow, spores by transmitted light, colorless, smooth or nearly so, 6-7.5 mu.

Of this species two specimens only are before us, one from Muscatine County, Iowa, and one from Washington (state). The species seems thus to have wide range, but to be exceedingly rare. It differs from all other American forms, so far described, in the peculiar development of the calyculus. Rostafinski emphasizes the persistence of the peridial wall and the peculiar gleaming of the metallic tints, displayed by all the structures. These particulars we have not been able to verify. Such characters may be incident to age or conditions of development. At all events, in forms which in all other respects seem to agree exactly with Rostafinski's descriptions, the colors are dull and without any noticeable iridescence. The spores in our specimens are also a little larger than quoted. Rostafinski gives 5-6 mu; Massee, 5-7 mu.

6. CRIBRARIA AURANTIACA _Schrader._

PLATE XVII., Fig. 3, and XIX., Fig. 7.

1797. _Cribraria aurantiaca_ Schrad., _Nov. Gen. Pl._, p. 5.

Sporangia gregarious, spherical, dusky or yellowish stipitate, nodding; the calyculus variable, generally prominent, more or less distinctly marked by fine, delicate radiating venules, the margin denticulate, the teeth numerous and slender, supporting the well-defined globose net; network made up of very tenuous threads, forming rather small irregular brownish nodules and showing only here and there a free extremity; stipe generally short, two or three times the diameter of the sporangium, sometimes longer, tapering upward, brown, slender, arcuate above; spore-mass yellow or ochraceous, spores by transmitted light, colorless, 5-6 mu, almost smooth.

This widely distributed and very variable species is generally recognized by the large sporangia, .5-.9 mm., comparatively short stipe, simple net, and more or less orange color. The color is an uncertain thing even in the sporangia, which rise from one plasmodium. Schrader, however, made this feature so far diagnostic that he placed the more pronouncedly yellow forms in the species _C. aurantiaca_ and set off as _C. vulgaris_ forms in which more dusky tints prevail. The dark-colored forms have also usually longer stipes, but so much is dependent upon the climatic conditions prevalent at the time of fruiting, that this feature also is indeterminate. Rostafinski's figures, 21 and 26, Tab. II., show the characteristic nodules and the typical net structure. It is to be observed that Fig. 21 represents higher magnification; otherwise the two figures are very much alike.

New England, New York, Pennsylvania, Maryland and South, Ohio, Washington, California; Canada, Toronto.

7. CRIBRARIA DICTYDIOIDES _Cke. & Balf._

PLATE I., Figs. 5, 5 _a_, 5 _b_, and XIX., 6, 6 _a_, 6 _b_.

1881. _Cribraria dictydioides_ Cke. & Balf., _Rav. Fung. Am._, 475.

Sporangia gregarious, of medium size, globose, cernuous, stipitate; the stipe long, slender, tapering upwards, dull brown in color; hypothallus none; the calyculus variable, sometimes well developed, as in _C. aurantiaca_, sometimes rudimentary or represented only by irregular, node-like ribs; the network delicate, the meshes small, few-sided; the nodules large, prominent, brown, irregular, with several radiating, free, projecting threads, beside the single continuous filaments which pass from node to node; spore-mass pale, ochraceous; spores nearly smooth, colorless, 5-7 mu.

This seems to be the most common _Cribraria_ in the Mississippi valley. It is generally distinguished by the scant calyculus and the beautiful richness of its clear delicate net. The stellate nodules especially above, emit filamental rays in all directions, but are, notwithstanding, united by single, unpaired threads only. The calyculus is often entirely absent, and this has been supposed the typical condition; but, on the contrary, there often may present itself a cup as distinct as in _C. aurantiaca_. See, for this variation, _Bot. Gaz._ XIX., p. 398. The rather large sporangia, .6-.7 mm., the nodes joined by single threads, the remaining radiant threads, many or few, but very short--these seem to be the most distinctly diagnostic characters, and these are sufficiently constant to separate this species easily from _C. intricata_ on the one hand and _C. tenella_ on the other. Mr. Lister considers this merely a form of the next species.

Abundant on rotten logs of every sort, especially oak; common on the lower side of rotting pine planks in wooden walks along the streets everywhere. N. A. F., 2095, seems to belong here.

Pennsylvania, Ohio, North Carolina, Missouri, Illinois, Iowa, Nebraska.

8. CRIBRARIA INTRICATA (_Schrad._) _Rost._

1797. _Cribraria intricata_ Schrad., _Nov. Gen. Pl._, p. 7.

Sporangia gregarious, globose, large, .7-1 mm. in diameter, nut-brown or olivaceous, erect, stipitate; stipe long, slender, purplish brown, flexuous; calyculus variable, sometimes occupying one-third of the sphere, when it is delicately costate, concolorous with the stipe, and passes over to the net by a distinctly toothed or serrulate margin, sometimes represented by irregular ribs or costae only; net well differentiated, the threads delicate, transparent, yellow, connecting large black nodules, running from one to the other in pairs or sometimes three together, free ends not numerous, the meshes few-sided, often triangular; spores in mass, dull olivaceous, under the lens pallid, nearly smooth, 6-7 mu.

A very rare species, if indeed it occur in this country. At least the form figured by Rostafinski, Tab. II., Fig. 27, and Massee, Pl. 1, Fig. 11, has not come to our notice. The parallelism of the net threads is a touch added by Rostafinski; Schrader does not mention it. Lister makes this species include the preceding. The form described in _Bull. Lab. Nat. Hist. Ia._ II., p. 119, is _C. dictydioides_.

Reported from New York, New England and Pennsylvania.

In the English _Monograph_ we are repeatedly assured that this species is common in the United States. The statement is made possible only by the inclusion of the form originally described from America and truly abundant east of the Rocky Mountains, _C. dictydioides_ Cke. & Balf.; _C. intricata_, by all accounts, just as preeminently the species of Europe. It is true that Schrader did not emphasize the parallel connecting threads by which later authorities distinguish the form; he had little occasion so to do, even did his figures intend accuracy in each detail, which they did not, and Rostafinski's, though his drawing is a diagram, certainly knew what he was doing. Cooke, in his list for Great Britain, quotes the Polish text without dissent, and Massee follows and illustrates; so that there can be no doubt as to what the European species is.

In any cribraria the presence or relative obsolesence, of the calyculus is of little taxonomic import since that structure is variable in every species. In the latest edition of Mr. Lister's work, the American form is entered as a variety in "hot-houses"; apparently adventitious; it is indeed related to the European form but is a geographic species.

9. CRIBRARIA PIRIFORMIS _Schrader._

PLATE XVII., Fig. 9; PLATE XIX., Fig. 9.

1797. _Cribraria piriformis_ Schrad., _Nov. Gen. Pl._, p. 4.

Sporangia gregarious, small, .3-.5 mm., turbinate or globose, erect, purplish brown, stipitate; stipe comparatively short, tapering upward, longitudinally furrowed, purple or brown; calyculus very well defined, about one-third the sporangium, not ribbed, flattened or even umbilicate below, the margin plainly denticulate, dusky brown; the net simple, the meshes large, triangular, with few free ends; the nodules small, globose or undifferentiated, slightly convex or flat; spore mass dull, yellowish brown; spores by transmitted light pale ochraceous or salmon-tinted, nearly smooth, 5-6 mu.

Schrader defined this beautiful form chiefly by its shape. This, though variable, is yet generally so far pyriform as to show distinct contraction toward the stipe. The well-defined calyculus is narrowed below and eroded or denticulate above. The cyanic tints due to the presence on the calyculus of radiating lines of purplish granules about one-half the size of the spores, the net open, uniform, the stipe rather stout, short, and distinctly furrowed, rising often from a small hypothallus--these are marks of this species. The net suggests _C. tenella_, but the latter species is much smaller, has a different stem, much longer and unfurrowed. The cup here is more nearly that of some form of _C. intricata_, but is better defined, passing into the net very abruptly by the simple intervention of projecting teeth.

Apparently rare. Our specimens are from New York, through the courtesy of Dr. Rex, Virginia, North Carolina, Iowa, Oregon, Colorado, and represent, as usual a modification of the European type, _C. notabilis_ Rex. Miss Lister, _Mon., 2nd ed._, writes var. _notabilis_.

Colorado forms are remarkable for dense brown coloration.

10. CRIBRARIA TENELLA _Schrader._

PLATE XVII., Fig. 5.

1797. _Cribraria tenella_ Schrad., _Nov. Gen. Pl._, p. 6.

Sporangia gregarious, small, .3-.5 mm. in diameter or smaller, olivaceous or ochraceous, long-stipitate, nodding; stipe slender, dark brown or blackish, very long, reaching 6 mm., weak and flexuous; calyculus variable, sometimes well defined, brown, costate, sometimes represented by the costae only connected by a thin, transparent membrane; net well differentiated, the meshes small, irregular, the nodes small, black, more or less globular, prominent, connected by transparent threads with occasional or a few free ends; spores in mass, olivaceous-ochraceous, under the lens pallid, globose, smooth, 5-7 mu.

Very common eastward and south, on the weathered surface of rotten wood. Generally easily recognized by its very long stipe, small, globose sporangium dotted with numerous small roundish nodules projecting plainly above the general surface. The obconic calyculus is always represented in the outline if not in definite structure.

New England, New York, Pennsylvania, Ohio, Tennessee, Illinois, Missouri, Iowa, Canada; Toronto,--_Miss Currie._

11. CRIBRARIA MICROCARPA (_Schrad._) _Persoon._

PLATE XVII., Fig. 4.

1797. _Dictydium microcarpum_ Schrad., _Nov. Gen. Pl._, p. 13. 1801. _Cribraria microcarpa_ Schrad., Pers., _Syn._, p. 190. 1875. _Cribraria microcarpa_ (Schrad.) Rost., _Mon._, p. 235. 1892. _Cribraria microcarpa_ Schrad., Massee, _Mon._, p. 63. 1893. _Cribraria microcarpa_ Schrad., Morg., _Myx. Mi. Vall._, p. 15. 1899. _Cribraria microcarpa_ Schrad., Macbr., _N. A. S._, p. 168. 1911. _Cribraria microcarpa_ Pers., Lister, _Mycetozoa, 2nd ed._, p. 183 (?).

Sporangia loosely gregarious, very small, .2-.3 mm. in diameter, yellow ochraceous, stipitate, nodding; stipe comparatively stout, dark brown or blackish, tapering upward, often twisted at the apex as in _D. cancellatum_; calyculus none, represented by simple ribs which give off at intervals free or floating branchlets before blending into the common net; net well developed, the meshes large, the nodes small, irregular, though often rounded and prominent, black, connected by delicate transparent threads, with free ends few or none; spore-mass yellow, fading to ochraceous; spores pale, smooth, globose, 6-7 mu.

This species resembles at first sight the preceding, and has been often mistaken for it. As a matter of fact, the distinctions are generally very sharp. In the first place, the sporangia, when carefully measured, are seen to be not more than half as great in diameter; the meshes of the net, on the other hand, are much wider, the whole structure more compact. The nodules are like those of _tenella_, but are much fewer. The stipe is shorter, the cup wanting, and the costae are few and simple. The color suggests _C. aurantiaca_. The habitat and distribution as _C. tenella_.

To anyone who will read the account of the species as given by the English _Mon., 2nd ed._, p. 183, it is immediately apparent that the author has in mind a different form from that seen and described in our territory and previously noted by the authors of Europe. These from Schrader down, agree in portraying a brunescent form with yellow spores; Mr. Lister enters it with the cyanic series and so describes and figures it throughout. Schrader figures a nut-brown species; Rostafinski uses that descriptive term in connection with the general appearance when fresh, but gives the spore-mass yellow; only in the stipe does he find another tint, nut-brown-purple. The figure, 145 in the _Monograph_ now before us portrays, except in color, our _C. tenella_ exactly. Dr. Rex, _Bot. Gaz._, XIX., 398, compares the present species with _C. minutissima_, and _C. tenella_ with _C. dictydioides_; which is correct for the American presentation of the species named. _C. dictydioides_ is certainly our presentation of _C. intricata_, a geographic species at the least; but if _C. microcarpa_ is purple we have of it no representation; our forms under that name are closely related to _C. tenella_, a yellow-spored species, and might perhaps be there referred; have, however, somewhat larger spores.

12. CRIBRARIA VIOLACEA _Rex._

PLATE XVII., Fig. 8.

1891. _Cribraria violacea_ Rex, _Proc. Phil. Acad._, p. 393.

Sporangia scattered or gregarious, very small, .2 mm. in diameter, violet tinted, erect, stipitate short, about one-half the total height, concolorous, slender, tapering upward; calyculus crateriform, persistent, or marked with minute plasmodic granules; the net rudimentary or poorly developed, the meshes large, irregular, the nodules also large triangular, violaceous; spores pale violet in mass, by transmitted light reddish, 7-8 mu, minutely warted.

A very minute but well-marked species discovered by Dr. Rex in Wissahickon Park, near Philadelphia, otherwise very rare. Lister, however, reports it from England. In minuteness to be compared with _C. minutissima_, from which its color instantly distinguishes it. Dr. Rex reports the plasmodium as "violet black." All our specimens are on very rotten wood, basswood, _Tilia americana_.

Pennsylvania, Illinois, Iowa.

13. CRIBRARIA PURPUREA _Schrad._

1797. _Cribraria purpurea_ Schrad., _Nov. Gen. Pl._, p. 8.

Sporangia gregarious, large, 1 mm. in diameter, dark purple, erect, stipitate, depressed-globose; stipe concolorous, furrowed, about twice the diameter of the sporangium in length, with a distinct hypothallus; calyculus persistent, less than half the sporangium, obscurely ribbed, marked by concentric plications, the margin toothed; the net poorly differentiated, the meshes irregular in form and size, as are also the flat, unthickened nodes, the threads pale, free ends short and not numerous; spore-mass purple; spores by transmitted light, pale or colorless, 5-6 mu, smooth.

Rare. Found on rotten coniferous wood in deep forests. Easily recognized by its large size and uniform purple color. To the next species it offers a general resemblance, but has larger sporangia and an entirely different net. The plasmodium just before the formation of the fruit is scarlet.

Maine, New York, Pennsylvania, Ontario, Oregon, Colorado.

14. CRIBRARIA ELEGANS _Berk. & C._

1873. _Cribraria elegans_ Berk. & Curt., _Grev._, II., p. 67.

Sporangia gregarious, erect or nodding, small, .4-.5 mm., bright purple, stipitate; stipe long, slender, tapering upward, almost black, arising from a scanty hypothallus; calyculus about half the sporangium, finely ribbed, covered especially above with small purple granules, the margin toothed or perforate; net well developed, the meshes small, polygonal, the threads delicate, colorless, with many free ends, the nodules dark-colored, numerous and somewhat prominent; spore-mass pale purple; spores by transmitted light pale violaceous, smooth, 6-6.5 mu.

To be compared with the preceding. The small-meshed net with well-defined, dark-colored nodules is distinctive, aside from the fact of the much smaller sporangia. The stipe is also different, more slender, smooth, and dark-colored. The habitat of the two species appears to be the same. The present species is much more common, ranges farther west, and is to be looked for on the Pacific coast.

New York, Pennsylvania, South Carolina, Missouri, Iowa; Black Hills, South Dakota.

15. CRIBRARIA LANGUESCENS _Rex._

1891. _Cribraria languescens_ Rex, _Proc. Phil. Acad._, p. 394.

Sporangia scattered, very minute, .25-.35 mm., spherical, long-stipitate, drooping; stipe 2.5-3 mm., slender, flexuous, subulate, rugulose; calyculus about one-third the sporangium, reddish brown, shining, minutely striate with granular lines, the margin more or less regularly serrate; net reddish brown, the meshes triangular and the threads simple, the nodes large, polygonal, flat, but well differentiated; the spores when fresh dull red in mass, paling with age; by transmitted light colorless, 6 mu, smooth.

A very singular species, easily recognizable by its long, slender stipes, terminating in exceedingly small spherical sporangia. The colors are obscure, but the striations on the calyculus are violet-tinted, and the reds perhaps predominate elsewhere. "In its scattered and solitary growth, its tall, slender stipes, and relaxed habit it resembles _C. microcarpa_, in its network it approaches _C. tenella_, and its spores have the color of the paler form of _C. purpurea_." So Dr. Rex, _l. c._ Western forms of the first-named species have much shorter stipes; the network in the specimens before us is unlike that of _C. tenella_, but resembles that of _C. purpurea_.

Rare, on very rotten wood, in the forest. New York, Ohio, South Carolina, Ontario.

16. CRIBRARIA CUPREA _Morgan._

PLATE XVII., Fig. 7.

1893. _Cribraria cuprea_ Morg., _Jour. Cin. Soc_., p. 16.

Sporangium very small, .33 mm., oval or somewhat obvoid, copper-colored, stipitate, nodding; stipe concolorous or darker below, subulate, curved at the apex, 2-4 times the sporangium; calyculus about one-half the sporangium, finely ribbed and granulose within, the margin nearly even; the net rather rudimentary, the meshes large, triangular or quadrilateral, the nodules also large, flat, concolorous, the threads slender, transparent, with free ends few; spores in mass copper-colored, by transmitted light colorless, smooth, 6-7 mu.

Recognizable by its small size and peculiar color, that of bright copper, although this fades somewhat with age, and the metallic tints are then lacking. Related to the preceding and in specimens having globular sporangia closely resembling it; but the ground color in _C. languescens_ is always darker, and the stipe proportionally much longer. In habit the sporangia are widely scattered, much more than is common in the species of this genus. Miss Lister, _2nd ed._ regards this as a var. of No. 15.

Comparatively rare. Before us is one very small colony of sporangia from Iowa, one from Ohio, and a large number from Missouri. If one may judge from the material at hand, the favorite habitat is very rotten basswood, _Tilia americana_.

=2. Dictydium= (_Schrad._) _Rost._

Sporangia distinct, gregarious, globose or depressed-globose, stipitate, cernuous; the peridium very delicate, evanescent, thickened on the inside by numerous meridional costae which are joined at frequent intervals by fine transverse threads more or less parallel to each other, forming a persistent network of rectangular meshes.

The ribs or costae of the spore-case radiate from the top of the stipe and unite again at the top of the sporangium in a feeble, irregular net. Schrader, _Nov. Gen. Pl._, p. 11, 1797, applied the name _Dictydium_ to all _Cribraria_-like species in which the calyculus was wanting. Fries follows this, _Syst. Myc._, III., p. 164. Rostafinski, _Versuch_, p. 5, _Mon._, p. 229, first correctly limits the genus and separates it from _Cribraria_. 1873-75.

A single species is widely distributed throughout the world,--

1. DICTYDIUM CANCELLATUM (_Batsch_) _Macbr._

PLATE I., Figs. 6, 6 _a_ and PLATE XIX., Figs. 1, 1 _a_, 1 _b_, 1 _c_, 2, 3.

1789. _Mucor cancellatus_ Batsch, _Elench. Fung._, II., p. 131. 1797. _Dictydium umbilicatum_ Schrad., _Nov. Gen. Pl._, p. 11. 1801. _Cribraria cernua_ Pers., _Syn._, p. 189. 1816. _Dictydium cernuum_ Nees, _Syst. d. Pilz._, p. 117. 1875. _Dictydium cernuum_ (Pers.) Rost., _Mon._, p. 229. 1893. _Dictydium longipes_ Morg., _Cin. Soc. Jour._, p. 17, in part.

Sporangia gregarious, depressed globose, nodding, the apex at length umbilicate, stipitate, in color brown, or brownish purple; the stipe varying much in length from two to ten times the diameter of the sporangium, attaining 5-6 mm., generally erect, more or less twisted and pallid at the apex, below dark brown, with hypothallus small or none; calyculus often wanting, when present a mere film connecting the ribs of the net; the net made up chiefly of meridional ribs connected at intervals by transverse parallel threads, above an open _Cribraria_-like network closing the apex and more or less rudimentary; the spores varying in color through all shades of brown and purple when seen in mass, by transmitted light reddish, 5-7 mu, smooth or nearly so.

This species in the United States is one of the most variable in the whole group. The extremes of such variation might easily constitute types for several distinct species were it not that in all directions the varieties shade into each other so completely as to defy definition. We have before us specimens purple throughout and short-stemmed; purple with stem long, pale and twisted at apex; brown, with the same variations; short-stemmed, with the apex of the stem pallid, and long-stemmed, with and without the same peculiarity. Morgan (_Cin. Soc. Nat. Hist. Jour._, 1893) would set off the purple, long-stemmed forms as _D. longipes_, "stipe three to five times the sporangium," but here are forms in which the stem is ten times the diameter of the sporangium, which yet possess in all other particulars the characters of the short-stemmed forms. European forms also vary. Massee figures one type; Lister, one or two others; Rostafinski's figure indicates a taller form; Fries says, "Stipes elongatus, peridio quinquies et ultra longior." It seems reasonable to suppose that the variation is largely due to atmospheric conditions at the time of fruiting. The purple forms may be cases of arrested development, since the plasmodium appears to be in all cases purple, or at least they seem to represent those plasmodia which have failed of normal ripening. We may recognize two or three general types, distinguished primarily by color:--

a. _D. cancellatum cancellatum._--Sporangia clear brown or with only a purplish tinge, the stipe tapering upward, and in extreme cases perfectly white at the twisted apex. The stipe in length ranges from three to ten times the diameter of the sporangium. The reticulations of the net are generally small and the ribs numerous. This is the most highly differentiated, finished type of the species.

b. _D. cancellatum purpureum._--Sporangium dark, the purple tints predominating, the stipe tapering upward, more or less twisted at the paler, sometimes almost colorless, apex. The stipe ranges a little shorter than in the preceding variety, three to seven times the sporangium. The reticulations of the net are often coarse, the ribs being fewer; the whole structure weak and showing signs of imperfect development.

The figures, 1, 1 _a_, 1 _b_, 1 _c, l. c._, illustrate the ideal accomplishment in form (a). The color is a clear definite brown with no suggestion of purple anywhere. The stipes are three or four times the diameter of the sporangium, brown below, white above, and twisted to allow the sporangium to hang inverted. This is complete in every part; a definite bell-shaped calyx, widening into the cancellate receptacle, the margin constricted, and closed at last by the apical net, _cribrum_, sign of the order.

In form (b), the structure is similar but by no means so symmetrical and complete. The calyx often fails, or is present by obscure indications only. The cancellation is coarser, the number of ribs fewer, the whole sporangium more or less globose; ferruginous or purple, the prevailing tint. Figs. on Pl. 1. are from the ferruginous type.

Figure 3 represents a beautiful thing; cup-less, ellipsoidal, delicate, of average size and in every way well-proportioned, clear rosy brown in color.

This may stand for a third variety; (c) _D. cancellatum prolatum_.

Common everywhere. The fruit appears in June on decaying logs and stumps of various species of deciduous trees, conifers, etc., the finest, and greatest variety, are from southern Missouri.

ORDER IV

=LYCOGALALES=

Fructification aethalioid; peridium membranaceous, tough, simple, without vesiculose with protoplasmic masses, within gelatinous; the capillitium of cortical origin, consisting of irregular lobate or branching tubules, varying much in width, and marked by numerous corrugations, irregular warts or bands; spores minute, ashen or pallid.

This order includes but a single genus,--

=Lycogala= _Micheli._

1729. _Lycogala_ Micheli, _Nov. Plant. Gen._, pp. 216, 217. 1753. _Lycoperdon_ Linn. _Syst. Nat._, in part. 1794. _Lycogala_ Persoon, Roemer, _N. Bot. Mag._, p. 87.

Micheli's description and figures, _Nov. Plant. Gen._, pp. 216, 217, Tab. 95, leave no doubt but that this illustrious man had species of _Lycogala_ before him when he described the genus. His figure 1. no doubt portrays the second species in our present list. More recent writers, from Persoon down, have used Micheli's designation, but differed in regard to the limits to which the name should be applied. It is here used substantially as in 1729. Fries and, after him, Rostafinski make a mistake in quoting Retzius as writing _Lycogala_ (1769). Retzius wrote _Lycoperdon sessile; Kongl. Vetenskaps Acad. Handling, foer Ar._ 1769, p. 254.

=Key to the Species of Lycogala=

_A._ Aethalia irregularly globose.

_a._ Cortex minutely roughened or warted; about 12 mm. in diameter 1. _L. epidendrum_

_b._ Cortex smooth, size large 2. _L. flavo-fuscum_

_c._ Cortex rough; diameter 6 mm. or less 3. _L. exiguum_

_B._ Aethalia conical 4. _L. conicum_

1. LYCOGALA EPIDENDRUM (_Buxb._) _Fries._

1721. _Lycoperdon epidendron_, etc., Buxb., _En. Pl. Hal._, p. 203. 1753. _Lycoperdon epidendrum_ Linn., _Sp. Pl._, p. 1184. 1829. _Lycogala epidendrum_ (Buxb.) Fries, _Syst. Myc._ III., p. 80.

Aethalia solitary or clustered, depressed spherical, or, when crowded, irregular, olivaceous or blackish, minutely warted, 3-10 mm. in diameter, dehiscing irregularly, but more often near the apex; peridium thin, but tough and persistent, made up of numerous agglutinated tubules enclosing in their mashes peculiar cell-like vesicles; capillitium parietal, consisting of long, branching, and anastomosing flattened tubules extended inwardly among the spores, everywhere marked by transverse wrinkles, ridges, and warts, the free ends of the ultimate branchlets rounded, concolorous with the spores; spore-mass, when fresh, rosy, or ashen with a rosaceous or purplish tinge, becoming with age sordid or ochraceous, spores by transmitted light colorless, minutely roughened or reticulate, 5-6 mu.

This is not only a cosmopolitan species, but is no doubt, the most common slime-mould in the world. Found everywhere on decaying wood of all sorts, more particularly on that of deciduous trees. It has likewise been long the subject of observation. It is doubtless the "_Fungus coccineus_" of Ray, 1690, and the type of Micheli's genus as here, 1729. The different colors assumed, from the rich scarlet of the emerging plasmodium to the glistening bronze of the newly formed aethalium, have suggested various descriptive names,--as _L. miniata_ Pers., _L. chalybeum_ of Batsch, and _L. plumbea_ Schum. The peridium is by authors described as double. This is for description only. In structure the outer and inner peridium completely blend. The outer is predominately vesiculose, the inner more gelatinous. For discussion of the microscopic structure see under the next species.

Common. New England, west to Nebraska, South Dakota, Colorado, Washington, Oregon, California; Alberta to Nicaragua.

_Lycogala terrestre_ Fr., _Syst. Myc._, III., 83, appears to be a variety of the present species. In spores and capillitial thread the forms are indistinguishable; the difference is a matter of size, and to some extent, of the color of the wall. The specimens are a little larger, depressed and angular. The peridium is paler, smoother, though sometimes almost black, thin, ruptured irregularly. But the form and color of the peridium in the sporocarps of the older species vary much in response to external conditions; on a substratum affording scant nutrition the forms of fructification are minute; and in all cases, if maturity be hastened, the peridium responds in darker colors. Under more favorable conditions the wall is smoother and brighter.

2. LYCOGALA FLAVO-FUSCUM (_Ehr._) _Rost._

1818. _Diphtherium flavo-fuscum_ Ehr., _Syl. Myc. Berol._, p. 27. 1829. _Reticularia flavo-fusca_ (Ehr.) Fries, _Syst. Myc._, III., p. 88. 1873. _Lycogala flavo-fuscum_ (Ehr.) Rost., _Versuch_, p. 3.

Aethalia solitary or sometimes two or three together, large 2-4 cm. in diameter, spherical or spheroidal, purplish-gray or brown, smooth, shining; the peridium thick, simple but in microscopic section showing two or three successive layers; capillitium of abundantly branching, irregular, transparent tubules, marked by numberless warts and transverse rings or wrinkles, spores in mass yellowish gray, by transmitted light, colorless, smooth or only faintly reticulate or roughened, 5-6 mu.

This, one of the largest and most striking of the slime-moulds, is by students generally mistaken for a puff-ball. It occurs on stumps and rotten logs of various sorts in the Mississippi valley, more often affecting stumps of _Acer saccharinum_ L. The fructification, when solitary, about the size of a walnut, though sometimes larger; when clustered, the individuals are smaller. The form depends largely upon the place in which the fruit is formed. The plasmodic mass is so large that its form is determined by gravity. Thus on the lower surface of a log raised a little distance from the earth the aethalium is often pyriform. This fact did not escape Micheli. See _Nov. Plant. Gen._, Tab. 95. The plasmodium is pale pink, soon becomes buff when exposed in fruiting, finally pallid or somewhat livid, and is outwardly changed into the stout, tough peridium. This consists of an intricate network of irregular gelatinous tubules enclosing within the meshes protoplasmic masses of pretty uniform size, 60-100 mu. Outwardly the protoplasmic vesicles predominate; inwardly the gelatinous tubules, which are, in some instances at least, continued toward the centre of fructification to form the capillitium. The protoplasmic masses referred to respond to ordinary stains, are often broken into numberless small cells corresponding in size and appearance to ordinary spores.

Not common. New England, Ohio, Iowa. Perhaps more abundant in the Mississippi valley; Canada.

3. LYCOGALA EXIGUUM _Morg._

1893. _Lycogala exiguum_ Morg., _Jour. Cin. Soc._, p. 8.

Aethalia small, 2-5 mm. in diameter, gregarious, globose, dark brown or black, sessile, minutely scaly, irregularly dehiscent; the peridium thin, the vesicles comparatively few, in irregular patches which are more or less confluent; capillitium as in preceding species, the tubules slender and branching; spore-mass pale, ochraceous, spores by transmitted light colorless, almost smooth, 5-6 mu.

Found in the same situations as No. 1, and at the same season. Recognizable by its _gregarious_ habit, not crowded nor superimposed, small size, and dusky color. The little spheres occur a dozen or more in a place, dark lead-colored, shading to black, opening rather regularly at the top. It looks like a depauperate _L. epidendrum_, but seems to be constantly collected.

Our specimens are from Ohio, Iowa, Missouri, Canada.

4. LYCOGALA CONICUM _Pers._

1801. _Lycogala conica_ Pers., _Syn. Fung._, p. 159. 1875. _Dermodium conicum_ (Pers.) Rost., _Mon._, p. 284.

Aethalia scattered, sometimes two or three together, small 2-4 mm. high, conical, sessile, pallid, grayish brown, marked by obscure black reticulations, opening regularly at the somewhat acuminate tip; peridium thin in structure, as in _L. epidendrum_, but more delicate; capillitium made up of abundant, slender, uniform threads almost smooth, simple, the free ends obtuse, taking origin in the cortex much as in the preceding species; spores in mass ochraceous, by transmitted light colorless, minutely warted or faintly reticulate, about 5 mu.

A very distinct and rare little species. Well described by Persoon, who also appears to have observed the plasmodium "_primo rubra_." The color of the mature form varies with age; at first somewhat purplish. Dr. Rex collected it in Pennsylvania; Mr. Morgan has it from Ohio; our specimens are from southeastern Missouri.

ORDER V

=TRICHIALES=

Fructification sporangial, rarely plasmodiocarpous, the sporangia stalked or sessile, gregarious or closely crowded, limeless throughout; the capillitium of definite threads, free or attached to the sporangial wall, isolated or combined into a net; spores generally some shade of yellow, never purple or black.

The distinguishing feature in this order is found in the peculiar sculpture of the capillitial threads. This is suggested by the tubules of _Lycogala_, though probably the resemblance is superficial only. The individual threads, as in _Trichia_, are called elaters, from their probable efficiency in spore-dispersal.

As here limited, the order is coextensive with the _Calonemeae_ of Rostafinski, except that that includes in addition the genera _Prototrichia_ and _Dianema_. The course of differentiation may be assumed to start with _Dianema_, through the _Perichaenaceae_ to the _Arcyriaceae_ and again from the same starting-point through _Prototrichia_ to the _Trichiaceae_.

=Key to the Families of the Trichiales=

_A._ Capillitial threads transverse to the sporangial cavity, attached usually at each end, plain or only slightly roughened _Dianemaceae_

_B._ Capillitium plain, papillose, or spinulose, often scanty, not netted, the threads sometimes attached by one end to the sporangium wall _Perichaenaceae_

_C._ Capillitium a distinct net, usually attached below to the sporangial wall; sculpture various, not continuous spiral bands _Arcyriaceae_

_D._ Capillitial threads transverse, fascicled, attached at both ends, but sculptured by well defined spiral bands _Prototrichiaceae_

_E._ Capillitial threads typically free, sometimes more or less branched, forming a loose net attached below, characterized by definite spiral bands, or sometimes by scattered rings _Trichiaceae_

_A._ DIANEMACEAE

=Key to the Genera of the Dianemaceae=

_A._ Capillitial threads attached at one end, or free 1. MARGARITA

_B._ Capillitial threads attached at each end 2. DIANEMA

=1. Margarita= _List._

1894. _Margarita_ Lister, _Mycet._, p. 203.

Sporangia sessile, the capillitium simple, hair-like, coiled.

1. MARGARITA METALLICA (_Berk. & Br._) _List._

PLATE XVII., Figs. 1, 1 _a_, 1 _b_.

1838. _Physarum metallicum_ Berk. & Br., _Mag. Zool. & Bot._, I., p. 49.

Sporangia scattered or clustered, globose, or somewhat plasmodiocarpous, .5-1 mm., sessile, coppery iridescent, the peridium thin, opening above irregularly; capillitium of long flexuous, coiling, simple or little dividing threads, nearly smooth, with infrequent attachments to the peridial wall; spores in mass yellowish, transparent under the lens, delicately verruculose, 10-12 mu.

One of the handsomer species of the present group. So far a Pacific coast form. California, Oregon, Washington; reported from Chile.

=Dianema= _Rex_

1891. _Dianema harveyi_ Rex, _Proc. Phil. Acad._, p. 397.

Sporangia simple or plasmodiocarpous; capillitium composed of threads without characteristic thickenings running entirely across the sporangium attached both to the base and to the opposite wall, not joined to form a network.

=Key to Species of Dianema=

_A._ Sporangia distinct, iridescent 1. _D. harveyi_

_B._ Fructification more or less plasmodiocarpous, dull brown 2. _D. corticatum_

_C._ Sporangia, some of them stipitate 3. _D. andersoni_

1. DIANEMA HARVEYI _Rex._

PLATE XVI., Figs. 5 and 5 _b_.

1891. _Dianema harveyi_ Rex, _Proc. Phil. Acad._, p. 397.

Sporangia gregarious, generally rounded or cushion-shaped, depressed, sessile, iridescent bronze, 1 mm. in diameter; peridium thin, translucent, opening irregularly; capillitium of simple threads, not netted, but often forked two or three times, taut, running from base to top; spores yellow, by transmitted light pale yellowish, minutely roughened, 8-10 mu.

This interesting species was collected in Orono, Maine, in 1889, by Professor F. L. Harvey, and so far as can be learned has not been taken since. Mr. Lister records two species from England which he refers to this genus. As to its systematic place, Dr. Rex says, _l. c._ "It stands as a single representative of a new and separate family adjoining the _Perichaenacae_ in the order _Calonemeae_ of Rostafinski."

Rare. Maine.

2. DIANEMA CORTICATUM _List._

PLATE XVI., Figs. 5 _a_, 5 _c_.

1894. _Dianema corticatum_ List., _Mycetozoa_, p. 205.

"Plasmodium pink"; sporangia sometimes flat-hemispheric, more often ill-defined, united in irregular, depressed, netted plasmodiocarps, generally dull brown; peridium opaque, didermatous, capillitium of simple or rarely branching filaments, variously beaded or marked with spiral bands, lightly attached at either end, occasionally twisted together; spore-mass dull brown, the spores in clusters of four or more, colorless by transmitted light, more or less verruculose, ellipsoidal, about 8-10 mu.

Our specimens are from the mountains of Alberta.

A curious, flat plasmodiocarp, an inch or more in length. It suggests _Hemitrichia serpula_ prematurely dry.

3. DIANEMA ANDERSONI, _Morg._

_Dianema andersoni_, _Morg._ MS., _non. pub._

Sporangium globose, sessile or sub-stipitate, seated on a thin brownish hypothallus; the wall a thin smooth pinkish membrane, when dry rugulose and iridescent, the inner surface somewhat thickened below and brownish at the base. Capillitium arising out of the thickened base, the threads hyaline or pinkish, ascending, flexuous, simple, or branched a time or two, the extremities attached on all sides to the wall of the sporangium. Spores globose, very minutely warted, pale, pinkish, 10-11 mu, in diameter, free.

Growing on old wood and bark of _Alnus_; British Columbia, _W. B. Anderson_.

Sporangium spherical, 6-8 mm. in diameter, sessile or on a very short stipe. This species differs from D. harveyi Rex in the _uniform pinkish_ color of the wall and of the spores; the dividing threads are furnished remotely with minute roundish tubercles as in _Didymium_; the spores are somewhat larger than in _D. harveyi_.

_B._ PERICHAENACEAE

=Key to the Genera of the Perichaenaceae=

_A._ Sporangia more or less plasmodiocarpous in type, terete; dehiscence irregular 1. OPHIOTHECA

_B._ Sporangia more or less polygonal in outline, or round, depressed; dehiscence circumscissile 2. PERICHAENA

=1. Ophiotheca= _Currey_.

1869. _Ophiotheca pallida_ Berk. & C., _Jour. Linn. Soc._, X., p. 350.

Fructification generally plasmodiocarpous, terete, bent or flexuous, often annular or cornuate, rarely globose, opening irregularly, peridium thin, not polished, covered more or less strongly with a distinct layer of scales or granules; capillitium of slender, loosely branching filaments, the surface rough to strongly spinulose; spores yellow.

As a generic name _Ophiotheca_ plainly has priority. _Cornuvia_ as understood by Rostafinski has no representative so far in our region.

=Key to the Species of Ophiotheca=

_A._ Plasmodiocarp usually upon herbaceous stems, slender 1. _O. vermicularis_

_B._ Plasmodiocarp on rotting bark, logs, etc,

_a._ Pale brownish or yellowish 2. _O. chrysosperma_

_b._ Chestnut brown or blackish 3. _O. wrightii_

1. OPHIOTHECA VERMICULARIS (_Schw._) _Macbr._

1834. _Physarum vermicularis_ Schw., _N. A. F._, No. 2296. 1869. _Ophiotheca pallida_ Berk. & C., _Jour. Lin. Soc._, X., p. 350. 1873. _Ophiotheca umbrina_ Berk. & C. Grev., II., p. 88. 1876. _Perichaena pallida_ (Schw.) Rost., _Mon. App._, p. 34.

Plasmodiocarp very slender, terete, elongate, flexuous or reticulate, annular, etc., of dull gray or neutral tint; the peridium thin, translucent, but with a delicate granular outer coating; capillitium of slender threads, frequently branched, warted and usually minutely spinulose; spore-mass ochraceous yellow; spores by transmitted light pale yellow, minutely roughened, 10 mu.

Perhaps common, but seldom collected, probably overlooked on account of protective coloration; the color is about that of the habitat, the weathered surface of dead herbaceous stems and roots. On dead corn stalks not infrequent. Differs from other species of the genus in having smoother capillitium, for which reason Rostafinski calls the present species _Perichaena vermicularis_. _O. pallida_ Berk. & C. seems to us to be the same thing, _N. A. F._, 726.

New England, New Jersey, South Carolina, Ontario, Ohio, Iowa.

2. OPHIOTHECA CHRYSOSPERMA _Currey_.

1854. _Ophiotheca chrysosperma_ Currey, _Quart. Mic. Jour._, II., p. 240. 1875. _Cornuvia circumscissa_ (Wallr.) Rost., _Mon._, p. 290. 1911. _Perichaena chrysosperma_ Lister, _Mycetozoa, 2nd ed._, in part, p. 248.

Plasmodiocarp elongate, bent and curved in various ways, spherical, more rarely annular or even reticulate, yellowish or ochraceous brown, opening irregularly; peridium thin, with yellowish outer layer; capillitium rather abundant, of threads slender, sparingly branched and minutely but distinctly spinulose; spore-mass yellow, spores by transmitted light pale, almost smooth, about 8 mu.

Occurs on the inner bark of deciduous trees, especially of oak. Not common.

This is possibly _Cornuvia circumscissa_ (_Wallr._) of Rostafinski's monograph; but it is doubtful to what Wallroth referred. Rostafinski's other citations are equally uncertain. Currey's figures and description alone merit recognition.

Ohio, Iowa, Tennessee; Canada.

3. OPHIOTHECA WRIGHTII _Berk._

PLATE II., Figs. 7, 7 _a_, 7 _b_.

1868. _Ophiotheca wrightii_ Berk. & C., _Jour. Linn. Soc._, X., p. 349. 1876. _Cornuvia wrightii_ (Berk. & C.) Rost., _Mon. App._, p. 36. 1892. _Cornuvia wrightii_ (Berk. & C.) Macbr., _Bull. Lab. Nat. Hist. Ia._, II., p. 122. 1911. _Perichaena chrysosperma_ Lister, _Mycetozoa, 2nd ed._, p. 248.

Plasmodiocarp bent or short-flexuous, often arcuate or completely annular, dark chestnut brown or black, opening irregularly; peridium thin, brittle, translucent, covered without by a rather dense layer of brownish or black brown scales; capillitium of long, sparingly branched threads furnished with projecting spinules remarkable for their length, about twice the diameter of the thread; spores yellow, minutely but distinctly warted, about 12 mu.

This is the common species everywhere on the inner side of the bark of fallen trees, _Ulmus_, etc. It is readily distinguished at sight by the peculiar annular, looped, and U-shaped plasmodiocarps, with their dark umbrine or blackened surface. From the preceding it is especially distinguished by the spinulose capillitium and larger spores.

Not rare. New England, New York, Pennsylvania, Ohio.

=2. Perichaena= _Fries_

1817. _Perichaena_ Fries, _Symb. Gast._, p. 11.

Sporangia flattened, sometimes small and roundish, more often larger, polygonal by mutual interference, or irregular, the peridium thickened outwardly by a dense reddish or brownish layer of scales; dehiscing by circumscission or by a lid; capillitium often scant, of slender, warted, yellowish threads, attached betimes to the upper wall; spores yellow, oval or spherical.

=Key to the Species of Perichaena=

_A._ Sporangia plainly flattened.

_a._ Very flat, sporangia 1mm. or more in width 1. _P. depressa_

_b._ Depressed; sporangia smaller 2. _P. quadrata_

_B._ Sporangia more or less spherical

_a._ Chestnut brown 3. _P. corticalis_

_b._ Gray or canescent 4. _P. marginata_

1. PERICHAENA DEPRESSA _Libert._

PLATE XVII., Fig. 10.

1837. _Perichaena depressa_ Lib., _Fl. Crypt. Ard._, IV., No., 378.

Sporangia sessile, applanate, crowded, polygonal by mutual contact, fuscous or chestnut brown, shining, opening by a definite lid; spore-mass and capillitium yellow, the capillitium well developed, of slender yellow threads of various widths, almost smooth; spores minutely warted, 10-12 mu.

Easily recognized by the peculiar, polygonal, depressed-flattened sporangia and consequent shallow spore-cases in which lie the yellow spores and scanty capillitium. Rostafinski refers here _P. vaporaria_ Schw., No. 2311, but the meagre description seems rather to apply to the next species. The original material is no longer accessible.

In the crevices and on the inside of bark of fallen logs of various sorts, walnut, maple, etc.

Not commonly collected. Specimens are before us from New England, Illinois, Iowa, Missouri, Florida, Mexico, Nicaragua. Probably over the whole wooded region of the continent.

2. PERICHAENA QUADRATA _Macbr._

1893. _Perichaena irregularis_ Berk. & C., Morgan, _Jour. Cin. Soc._, p. 20.

Sporangia very small, less than 1/2 mm., crowded, polygonal or quadrangular, depressed, but not flattened, smooth, bright rufous or brown; the peridium rather thick, yellow within, the dehiscence circumscissile; capillitium scanty, of slender, sparingly branched filaments, the surface minutely roughened, warted or spinulose; spore-mass yellow; by transmitted light pale yellow, 9-11 mu.

Differs from the preceding by the much smaller size of the sporangia, different color and habit. The sporangia, while depressed, still maintain considerable rotundity; they are occasionally quite spherical, and then of very uneven size, hardly in contact. In some cases the plasmodium before maturing seems to assume the form of a plasmodiocarp, which, by transverse fission at intervals, forms the curious four-sided conceptacles. At other times the plasmodium assumes the shape of a flat cushion or plate, which then subdivides into minute polygonal segments. This form has been known some years to collectors, and, if named at all, has been called _P. irregularis_. Lister, _l. c._, assures us that Berkeley's type "is typical _P. depressa_."

Not common. Pennsylvania, Ohio, Illinois, Missouri.

3. PERICHAENA CORTICALIS (_Batsch_) _Rost._

PLATE II., Figs. 1, 1 _a_, 1 _b_.

1783. _Lycoperdon corticale_ Batsch, _Elench. Fung._, p. 155. 1875. _Perichaena corticalis_ (Batsch) Rost., _Mon._, p. 293. 1817. _Perichaena populina_ Fries, _Symb. Gast._, p. 12.

Sporangia sessile, gregarious, flattened, hemispherical; peridia simple, opening by a lid; dehiscence circumscissile, the upper part chestnut brown, the lower almost black; capillitium feebly developed, smooth, attached to the lid and usually coming away with it, bringing the brilliantly yellow spore-mass, and leaving a delicate, shining cupule adherent to the substratum; spores yellow, nearly smooth, 10-12 mu. On and under the bark of dead elms of various species.

A very handsome little species occuring rarely with us, or perhaps overlooked by virtue of its protective coloration. Found sometimes on the inner side of the bark where the latter has separated, but not yet wholly parted company with the wood. In such situations the tiny sporangia are so nearly quite the color of the moist substratum as to escape all but the closest scrutiny. The dehiscence is very remarkable, characteristic, beautiful. Black, brown, chestnut, and gold are harmoniously blended, in the opening coffers. Prior to maturity the future line of fission is plainly indicated by the difference in color.

This is clearly the species found by Batsch "ligni demortui putridi in interiore corticis pagina." Bulliard has also described and figured the species, _Sphaerocarpus sessilis_ t. 417, Fig. V.

The capillitium is nearly smooth; the spores are only slightly roughened by minute warts.

Apparently not common. Iowa, Missouri; Black Hills, South Dakota; Canada;--_Miss Currie._

4. PERICHAENA MARGINATA _Schweinitz._

1831. _Perichaena marginata_ Schw., _N. A. F._, No. 2319, p. 258.

Sporangia depressed, globose, polygonal as they become approximate or crowded, hoary canescent, sessile; peridium rather thick, persistent, circumscissile in dehiscence, covered without by minute whitish calcareous (?) scales, within punctate by the imprint of the spores; hypothallus distinct, white; capillitium scant or none! Spores in mass dull yellow, by transmitted light pale, nearly smooth, 14-15 mu.

Lister, following Rostafinski, includes this form with the preceding. The differences between the two forms are, it seems to us, sufficient to make convenient their separation as by Schweinitz. Apart from the peculiar incrustation in the present species, the larger spores, and especially the peculiar white hypothallus, are distinctive. The method of dehiscence is also different. In _P. corticalis_ the line of cleavage before spore dispersal is indicated by a definite band surrounding the sporangium. Nothing similar appears in the gray specimens of the present form, although the dehiscence is quite as certainly circumscissile. The habitat in American specimens is the _outer_ surface of the bark, which causes the species generally, by protective coloration, to be overlooked.

Not common. Pennsylvania, Ohio, Missouri.

_C._ ARCYRIACEAE

=Key to the Genera of the Arcyriaceae=

_A._ Peridium becoming fragmentary, but persisting; capillitium non-elastic 1. LACHNOBOLUS

_B._ Peridium evanescent above, persistent below; capillitium elastic 2. ARCYRIA

_C._ Capillitium elastic, bearing hamate branches 3. HETEROTRICHIA

=1. Lachnobolus= _Fries_.

1829. _Lachnobolus_ Fries, _Syst. Myc._, III., p. 177.

Sporangia distinct, sessile or nearly so, globose or cylindric, often distorted, scattered or densely crowded, the peridium extremely thin, ruptured irregularly, and persistent in fragments; capillitium attached at numerous points to the sporangial wall, forming a dense net, the threads warted or spinulose, non-elastic.

Species of this genus are easily distinguished from those of the next by the peculiar fragile peridium and the inelastic capillitium.

=Key to the Species of Lachnobolus=

_A._ Sporangia pale yellow, on fallen flowers and fruit-burs of Castanea 1. _L. globosus_

_B._ Sporangia rosy or copper-colored, at length ochraceous 2. _L. occidentalis_

1. LACHNOBOLUS GLOBOSUS (_Schw._) _Rost._

1822. _Arcyria globosa_ Schw., _Syn. Fung. Carol._, No. 400. 1875. Lachnobolus globosus (Schw.) _Rost., Mon._, p. 283. 1894. _Arcyria albida_ Pers. (in part) Lister, _Mycetozoa_, p. 186.

Sporangia on the spines of fallen chestnut burs, scattered, pale yellow or whitish, small, globose, the peridium early evanescent above, more persistent below, stipitate; stipe small, tapering upward, from a small hypothallus; capillitium a dense but not expanding network attached chiefly to the lower portion of the sporangial wall, minutely waited or roughened, with few expansions or inflations; spores in mass pale yellow, under the lens colorless, almost smooth, 7-8 mu.

This singular little species is remarkable chiefly in the habitat it affects,--fallen chestnut burs. On these almost universal, but on nothing else, except on the fallen catkins of the same species. Regarded by Mr. Lister as _A. cinerea_, from which it differs constantly in form, in capillitium more open and with larger threads, 4-5 mu in diameter as well as in its unique habitat, and yellowish color.

Distribution coterminous with that of _Castanea dentata_ Borkhausen,--eastern half of the United States.

2. LACHNOBOLUS OCCIDENTALIS _Macbr._

PLATE II., Figs. 2, 2 _a_, 2 _b_; 4 and 4 _a_.

1885. _Lachnobolus incarnatus_ (Alb. & Schw.) Macbr., _Bull. Lab. Nat. Hist. Iowa_, II., p. 126.

Sporangia scattered or crowded upon a hypothallus more or less distinct, globose or ellipsoidal, short-stipitate, varying somewhat in color, at first rosy or flesh-colored, later brownish or ochraceous; the peridium exceedingly thin, pellucid, mealy, evanescent above, persisting as a shallow cup below; capillitium inelastic, rather closely netted of threads variable in thickness, marked by frequent thickenings or expansions, everywhere warted, attached to the peridial walls, spores in mass flesh-colored, under the lens colorless, smooth, globose, 7.5-9 mu.

This delicate and elegant little species appears to be not uncommon, but is probably generally passed over as an _Arcyria_, which it superficially resembles. When newly formed, the sporangia have a peculiar rosy or flesh-colored metallic tint, which is all their own. Within a short time this color passes, and most of the material comes from the field brownish or ochraceous in color. Typical sporangia are spherical on distinct short stipes; when crowded, the shape is of course less definite. The capillitium never expands as in _Arcyria_, but, exposed by the vanishing upper wall, remains a spherical mass resting upon the shallow cup-like base of the peridium.

This species has been in the United States generally distributed as _L. incarnatus_ (Alb. & Schw.) Schroet. A careful study of all descriptions of European forms and comparison of many specimens leads us to believe that we have here to do with a type presenting constant peculiarities. We have in America nothing to correspond with the figures of Schweinitz, Berkeley, or Lister. In the American gatherings the sporangia are uniformly regular, globose, very generally short-stipitate, more or less closely gregarious, never superimposed, or heaped as shown in Berkeley's figure, for instance, _Ann. and Mag. Nat. Hist._, IV., xvii., Pl. ix., Fig. 2. The plasmodium of our species is white; as it approaches maturity a rosy metallic tinge supervenes, quickly changing to dull yellow or alutaceous. The graphic description given by Fries of _Perichaena incarnata_, _Syst. Myc._, III., p. 193, presents scarcely a character attributable to the form before us. _L. congesta_ Berk. & Br., evidently the form figured and described by Lister, _Mycetozoa_, p. 194, Pl. lxx., B., resembles our species in color and capillitium, but is entirely different in habit.

Not uncommon. Maine, Iowa, Missouri, Nebraska.

=2. Arcyria= (_Hill_) _Pers._

1751. _Arcyria_ Sir John Hill, _Gen. Nat. Hist._, II., p. 47. 1801. _Arcyria_ Pers., _Syn. Fung._, p. 182.

Sporangia ovoid or cylindric or even globose, stipitate; the peridium thin, evanescent to near the base, the lower part persisting as a calyculus; the stipe variable, packed with free cell-like vesicles, resembling spores, but larger; capillitium attached below, to the interior of the stipe or to the calyculus, in form an elastic network, the tubules adorned with warts, spinules, half-rings, etc., but without spiral bands or free extremities.

Micheli, of course, discovered the arcyrias, put them in two genera and several species, which we may only dimly recognize. Persoon first saw distinctly the outlines of the genus as now understood and adopted the name given by Hill in his curiously prolix description of certain species, probably partly of the genus _Arcyria_, partly _Stemonitis_.

=Key to the Species of Arcyria=

_A._ Mature capillitium loosely adhering to the calyculus.

_a._ Mature capillitium far-expanded, drooping.

i. Dusky.

O Long, 12 mm. or more 1. _A. magna_

OO Shorter, about 6 mm. 2. _A. oerstedtii_

ii. Yellow 3. _A. nutans_

_b._ Mature capillitium short, not drooping, though sometimes procumbent.

i. Capillitium greenish yellow 4. _A. versicolor_