The Diatomaceæ of Philadelphia and Vicinity
Part 7
Valve linear-elliptical, with abruptly produced apices; ventral margin straight; median line almost straight; axial area narrow, central area large, rounded; striæ distant in the middle, closer at the ends.
Fresh water.
Pl. 18, Fig. 6.
CYMBELLA EHRENBERGII KUETZ.
Valve lanceolate, with ventral margin nearly straight and apices sub-rostrate; median line straight, excentric; axial area narrow; central area widened in the middle; striæ coarsely punctate.
Fresh water.
Pl. 18, Fig. 9.
{61}CYMBELLA AFFINIS KUETZ.
Valve about three times as long as broad, strongly convex on the dorsal side and straight on the ventral; apices sub-rostrate; striæ punctate; axial area narrow, not widened in the middle; median line curved; a small or indistinct punctum on the ventral side of the median line (not shown in the figure).
Common in ponds. Abundant in East Park Reservoir.
Pl. 18, Fig. 18.
CYMBELLA EXCISA (KUETZ.) DE TONI
Valve as in affinis, but with tumid and excised ventral margin; a punctum is found on the ventral side (not shown in the figure).
According to Cleve this is a variety of C. affinis.
Common in ponds.
Pl. 18, Figs. 15, 19?
CYMBELLA PARVA (WM. SM.) CL.
Valve semi-lanceolate, with produced apices; ventral margin slightly tumid; axial area narrow; striæ coarsely but obscurely punctate.
C. affinis and C. parva are quite variable, the latter differing by its lanceolate form and the absence of a punctum, which, however, is sometimes difficult to recognize. In a gathering of C. parva, it is quite possible to find numerous abnormal forms which appear to be sporangial, so that specific distinctions are difficult if based on occasional specimens.
Common in ponds.
Pl. 38, Fig. 14.
CYMBELLA AMPHICEPHALA NÆGELI
Valve unequally elliptical, with broad, rostrate apices; axial area narrow; median line straight; central area small, rounded; striæ, 12 in 10 µ on the dorsal, closer on the ventral, side and at the ends.
Kirkwood Pond, N. J.
Pl. 18, Fig. 16.
CYMBELLA SINUATA GREG.
Valve linear-elliptical, gibbous on the ventral side; axial area indistinct; central area widened on the ventral side nearly to the margin.
Crum Creek.
Pl. 18, Fig. 13.
SECTION 2.--COCCONEMA. FRUSTULES STIPITATE
CYMBELLA ASPERA (EHR.) CL.
Valve large, cymbiform, arcuate on the dorsal, slightly gibbous on the ventral side; axial area linear, broad, slightly widened in the middle; no row of puncta on the ventral side. The puncta form curved longitudinal lines and the innermost row on the ventral side appears sometimes distant from the others, but not as in C. cistula.
_Cocconema asperum_ Ehr.
_Cymbella gastroides_ Kuetz.
{62}Not Cymbella gastroides H. L. Smith, Type No. 118, which is C. mexicana A. S., having a punctum in the middle of the central nodule; in outline it is like C. gastroides var. minor Kuetz.
Blue clay.
Pl. 18, Fig. 1 (an unusual form, but it resembles Grunow's. (Diat. Franz Jos. Land, Pl. 1, Fig. 7.)
CYMBELLA CYMBIFORMIS (KUETZ.) BRÉB.
Valve cymbiform, slightly gibbous on the ventral margin; apices broad, somewhat truncate; a punctum occurs on the ventral side of the median line; striæ, 8 in 10 µ, closely punctate.
Kirkwood Pond, N. J.
Pl. 18, Fig. 2.
CYMBELLA CISTULA (HEMPR.) KIRCHN.
Valve cymbiform, with gibbous ventral margin and truncate apices; a distinct row of several puncta occurs below the median line in typical forms.
Blue clay.
Pl. 18, Fig. 3.
CYMBELLA LANCEOLATA (EHR.) KIRCHN.
Valve cymbiform, with gibbous ventral margin; apices truncate; axial area very narrow, scarcely widened in the middle; striæ with fine close puncta.
Kirkwood Pond, N. J.
Pl. 18, Fig. 4.
CYMBELLA MEXICANA (EHR.) A. S.
Valve broad, with gibbous ventral margin and sub-rostrate, truncate apices; median line with reflexed terminal fissures; striæ with coarse puncta; a large punctum occurs in the centre of the central area.
Blue clay.
Pl. 18, Fig. 5.
CYMBELLA TUMIDA (BRÉB.) V. H.
Valve cymbiform, with gibbous ventral margin and abruptly rostrate ends; median line arcuate; axial area narrow; central area large, orbicular; below the central nodule is a punctum; striæ punctate.
Crum Creek.
Pl. 18, Fig. 7.
SECTION 3.--ENCYONEMA. FRUSTULES IN TUBES
CYMBELLA VENTRICOSA KUETZ.
Valve lunate, with straight or slightly gibbous ventral margin; axial area indistinct; median line straight or nearly so; striæ punctate.
Very common, but extremely variable. The ventral margin is sometimes straight and sometimes quite gibbous.
Pl. 18, Figs. 14, 22; Pl. 38, Fig. 16; Pl. 40, Fig. 8.
{63}C. ventricosa is considered by some authors to be equivalent to C. affinis var. semicircularis Lagerst., Encyonema prostratum (Berk.) Ralfs, E. cæspitosum Kuetz. and E. auerswaldii Rab. H. L. Smith's Type Slide of C. ventricosa Ag. is said to equal C. affinis Kuetz., but the specimens appear to me to be equivalent to C. ventricosa Kuetz. Cleve unites many forms, including E. cæspitosum, under C. ventricosa.
CYMBELLA PROSTRATA (BERK.) CL.
Valve semi-elliptical, obtuse at the apices, which are sometimes prolonged and turned downwards; median line straight, terminal nodules distant from the ends; axial area narrow, central area rounded; striæ in radiating, slightly curved lines, indistinctly punctate.
Common in fresh water; occasional in brackish.
Pl. 18, Fig. 21 (represents a frequent variation).
CYMBELLA PHILADELPHICA N. SP.
Valve semi-elliptical-lanceolate, with rounded apices; ventral margin strongly gibbous; terminal nodules distant from the ends; axial area broad, central area widened on the dorsal side; striæ radiate, not curved nor of unequal length, indistinctly punctate, 10 in 10 µ on the dorsal, 8 in 10 µ on the ventral side. L. 86 µ.
This form approaches Encyonema prostratum (Berk.) Ralfs, Schmidt's Atlas, Pl. 71, Fig. 7, but differs in the striæ and the axial and central areas.
Blue clay of Philadelphia. Rare.
Pl. 18, Fig. 8.
CYMBELLA TRIANGULUM (EHR.) CL.
Valve semi-elliptical, with acute ends; median line straight; ventral side half the width of the dorsal, with straight, slightly convex or concave margin; striæ radiate, coarsely punctate.
_Gloeonema triangulum_ Ehr.
Baker's Run, Willistown, Pa.
Pl. 18, Fig. 24.
CYMBELLA TURGIDA (GREG.) CL.
Valve semi-elliptical, with acute ends; ventral margin gibbous; ventral side half the width of the dorsal; median line straight; terminal fissures turned downwards; axial area broad; striæ radiate, coarsely punctate.
Baker's Run, Willistown, Pa.
Pl. 18, Fig. 23.
CYMBELLA TURGIDA (GREG.) CL. VAR. ?
Valve lunate, with gibbous ventral margin; median line straight; terminal fissures turned downwards near the ends; axial area lanceolate, striæ radiate on the dorsal side, 8 in 10 µ, punctate, 9 on the ventral side, closer at the ends where they are convergent. L. 65 µ. Not a typical form.
Willistown, Pa.
Pl. 18, Fig. 12.
CYMBELLA RHOMBOIDEA N. SP.
Valve rhomboidal, with acute ends; dorsal part one and a half times the width of the ventral; median line nearly straight, with terminal fissures turned downwards near the ends; axial area broad, not widened in the middle, except slightly on the ventral side; striæ {64}radiate, distant in the middle of the dorsal side where they are 7 in 10 µ, coarsely punctate, the puncta in longitudinal lines, 9 in 10 µ on the ventral side, closer at the ends. L. 69 µ.
Baker's Run, Willistown, Pa.
Pl. 18, Fig. 11.
CYMBELLA GRACILIS (RAB.) CL.
Valve semi-lanceolate, with acute ends; median line nearly straight, with terminal fissures turned downwards, distant from the ends; axial area linear; ventral margin straight or slightly gibbous in the middle.
Hammonton Pond, N. J.
Pl. 18, Fig. 20.
CYMBELLA LACUSTRIS (AG.) CL.
Valve elliptical-lanceolate, with obtuse ends, nearly symmetrical; median line straight, terminal fissures distant from the ends; striæ radiate in the middle, convergent at the ends, coarsely lineate.
Belmar, N. J.
Pl. 18, Fig. 25.
AMPHORA EHR. (1840)
(amphora, a jar)
Valves asymmetrical along the longitudinal axis, as in Cymbella, but with the plane passing through the dorsal and ventral sides of one valve at an angle with that of the other. As Cleve states, Cymbella and Amphora are forms of Navicula "with both valves similar and asymmetrical along the longitudinal axis," and the difference between Cymbella and Amphora is in the "degree of asymmetry." If, following H. L. Smith's diagrams (Lens, Vol. 2, 1873, p. 66), we assume that the usual form of the valve in Navicula is elliptical or lanceolate, and the zone view is rectangular, we have in Cymbella an arcuate median line and a more or less reniform valve, while the zone view remains rectangular with the valves parallel. Now, if the valves are asymmetrical along the longitudinal axis, and one side of one valve is separated from the corresponding side of the opposite valve by a wider connective zone than is the case on the other side, the transverse section of the frustule will appear cuneate, as in Amphora, and the connective zone will be wider on one side than the other. When, therefore, we examine an entire frustule as it is usually seen, we shall find the two raphes of the valves in focus at the same time on the ventral side, and, by changing the focus, the convex sides of the same valves are seen, the dorsal view with, usually, a wider connective zone. As an illustration, compare Figs. 5 and 6, on Plate 15, Fig. 6 being the ventral, and Fig. 5 the dorsal view.
As Amphoræ are epiphytic or parasitic, they are considered, as Cleve remarks, like Achnanthes and Cocconeis, as "degenerated forms."
Chromatophores usually single, lying on the ventral connective zone. Mereschkowsky describes nine forms.
Cleve divides the genus into a number of groups as follows:
_Amphora proper._--Connective zone not complex; valves with longitudinal lines on the dorsal side; coarsely punctate or costate.
_Diplamphora._--Zone complex; otherwise as in Amphora.
_Halamphora._--Longitudinal lines absent; frustule elongate, with protracted ends.
{65}_Oxyamphora._--Zone complex; longitudinal lines absent; frustule elliptical; valve lunate, with or without a central stauros; striæ punctate.
_Amblyamphora._--Zone complex; frustule rectangular; valve lunate; striæ punctate; axial and central areas indistinct.
_Psammamphora._--Zone not complex; frustule rectangular; central nodule frequently dilated to a stauros; no axial or central area.
_Cymbamphora._--Valve semi-lanceolate; median line straight, approximate to the ventral margin.
AMPHORA
AMPHORA ROBUSTA GREG.
Frustule elliptical, truncate; valve lunate, with straight ventral margin; median line biarcuate; ventral side with coarse, radiate striæ, 6 in 10 µ, on both sides of the median line.
Along the coast.
Pl. 15, Fig. 1.
AMPHORA PROTEUS GREG.
Frustule elliptical, truncate; valve lunate, with straight ventral margin; median line biarcuate; no central area. Striæ on the dorsal side not interrupted, 9 in 10 µ. Ventral side striate toward the ends.
Differs from A. robusta chiefly in size and coarseness of puncta. Extremely variable in size.
Common along the coast.
Pl. 15, Figs. 5, 6, and 19.
AMPHORA OVALIS (BRÉB.) KUETZ.
Frustule elliptical, truncate; valve lunate; median line biarcuate; striæ on dorsal side 10-16 in 10 µ.
_Var. libyca (Ehr.) Cl._--Central area distinct on the dorsal side.
_Var. pediculus (Kuetz.) Cl._--Central area and nodule quite distinct. Striæ finer than in var. libyca.
Common in ponds. Quite variable.
Pl. 15, Fig. 7.
AMPHORA GIGANTEA VAR. FUSCA A. S.
Frustule elliptical; valve lunate, with straight ventral margin. Axial area absent on the dorsal side; dorsal striæ, 10 in 10 µ, punctate. Ventral part hyaline except at the ends, which are obliquely striated, with short, punctate lines. L. 70-120 µ.
Absecon, N. J.
Pl. 38, Fig. 1.
DIPLAMPHORA
AMPHORA CRASSA GREG.
Valve linear-elliptical, with obtuse, incurved ends. Median line biarcuate. Axial and central areas indistinct on the dorsal side; striæ coarsely punctate, interrupted by a longitudinal line on the dorsal side.
Along the coast.
Pl. 15, Fig. 3.
{66}AMPHORA AREOLATA GRUN.
Valve with straight ventral margin; median line straight, approximate to the ventral margin; axial area indistinct; several longitudinal lines crossed by apparent costæ which alternate with rows of fine puncta.
Blue clay. Rare.
Pl. 15, Fig. 11.
HALAMPHORA
AMPHORA COFFÆIFORMIS (AG.) KUETZ.
Frustule lanceolate, truncate; zone with numerous divisions. Valve arcuate on the dorsal and nearly straight on the ventral side; ends protracted or slightly capitate.
_A. aponina_ Kuetz.
_A. salina_ Wm. Sm.
Along the coast.
Pl. 15, Figs. 8 and 18.
OXYAMPHORA
AMPHORA LINEOLATA EHR.
Frustule membranaceous, elliptical, truncate, with broad ends. Zone with numerous divisions. Dorsal part striated transversely; ventral side with longitudinal lines.
_A. plicata_ Greg.
_A. hyalina_ H. L. Smith, Type No. 64.
Along the coast.
Pl. 15, Figs. 9 and 10.
AMPHORA OSTREARIA BRÉB.
Frustule oblong, with rounded angles. Zone with five or more divisions transversely striated. Central area narrow, biarcuate; central nodule dilated to a stauros. Valve narrow, with arcuate dorsal and straight ventral margin, acute at the ends. Striæ transverse, finely punctate.
_A. vitræa_ Cl.; _A. porcellus_ Kitton; _A. quadrata_ Bréb.; _A. elegans_ Greg. Appearance varies according to the position of the valve.
Along the coast.
Pl. 15, Figs. 12 and 21.
AMPHORA LÆVIS GREG.
Frustule oblong, hyaline and membranaceous. Valve linear or slightly arcuate, with ventral margin tumid in the middle; ends obtuse; central nodule dilated to a stauros; median line very narrow, biarcuate, coinciding with the dorsal margin at the ends; striæ transverse, punctate.
Blue clay.
Pl. 15, Fig. 13.
AMPHORA ACUTA GREG.
Valve lunate, with acute ends; ventral margin straight; ventral side very narrow. Central nodule dilated to a stauros; striæ transverse, punctate.
Along the coast.
Pl. 15, Fig. 20.
{67}AMBLYAMPHORA
AMPHORA OBTUSA GREG.
Frustule rectangular. Valve linear, obliquely rounded at the ends, with arcuate dorsal, and straight ventral, margin; median line biarcuate; striæ, 18-20 in 10 µ.
Along the coast. Common.
Pl. 15, Fig. 4.
PSAMMAMPHORA
AMPHORA ARENARIA DONK.
Frustule hyaline, rectangular, slightly tumid in the middle, with rounded angles. Valve linear with broad ventral side and straight or sinuate ventral margin. Striæ, 24-27 in 10 µ (Cleve).
Common along the coast.
Pl. 15, Fig. 17.
The distinction between A. obtusa and A. arenaria is not always evident if the valves alone are seen. The former has a complex zone, the latter a simple zone, and the valve has finer striæ. Cleve's descriptions and references in regard to these two forms do not agree with the descriptions and figures of H. L. Smith, or with the figures of Schmidt. The valves of most Amphoræ are capable of assuming various outlines according to their position.
AMPHORA OCELLATA VAR. CINGULATA CLEVE
Frustule rectangular. Valve linear, with dorsal margin arcuate and the ventral margin straight. Central nodule with a stauros on the dorsal side.
Squan River, N. J.
Pl. 15, Figs. 14 and 15.
CYMBAMPHORA
AMPHORA ANGUSTA VAR. EULENSTEINII GRUN.
Valve lanceolate, acute at the ends. Median line straight, approximate to the margin. Axial area widened on the dorsal side, indistinct on the ventral; striæ punctate.
_A. eulensteinii_ A. S.
Common along the coast.
Pl. 15, Fig. 16.
On Pl. 40, Figs. 21, 22, and 23, I have attempted, imitating H. L. Smith's figures (Lens, l.c.), to illustrate the difference in the transverse sections of Navicula, Cymbella and Amphora.
Fig. 21 represents the transverse section of a convex Navicula, in which the valves ecg and fdh are parallel, and the median nodules c and d are central.
Fig. 22 is a transverse section of Cymbella in which the valves are nearly parallel and the median nodules are excentric. The girdles on one side, ea and af, are narrower than gb and bh on the other side.
Fig. 23 is a transverse section of an Amphora in which the valves appear in zone view with the median nodules of both valves on the same side. The girdles on the ventral side, ea and af, are narrower than gb and bh on the dorsal side. The girdles on the dorsal side are seldom as broad as gb and bh, the valve extending over a great part of the dorsal side to g' and h'.
{68}AMPHIPRORA EHR. (1843)
(amphi, on both ends, and prora, a prow)
Frustule twisted in the longitudinal axis, constricted in the middle; zone complex, with numerous divisions crossed by fine striæ. Valve lanceolate, acute. The raphe confined within a sigmoid keel or extension of the valve; the central and terminal nodules indistinct. Striæ transverse, punctate, with coarser striæ at the junction of the keel and lower part of the valve.
Chromatophores single, with indented border except in A. pulchra, in which there are two chromatophores with entire borders.
AMPHIPRORA ALATA KUETZ.
Frustule with a row of puncta at the junction line. Valve linear, acute at the ends. Median line sigmoid. Striæ lineate on the lower part of the valve, punctate on the keel.
Along the coast. Not common.
Pl. 14, Fig. 3.
AMPHIPRORA PULCHRA BAIL.
Frustule with sigmoid connective zone. Valve very convex, with sinuate keel and junction lines evident. In zone view and in valve view, one half of the frustule, owing to the elevation of the keel, is wider than the other half. Striæ punctate, coarser on the keel.
Not uncommon along the coast.
Pl. 14, Figs. 1 and 2.
AMPHIPRORA CONSPICUA GREV.
Valve linear or elliptical, with acute ends. Median line sigmoid, but the junction lines not evident. Striæ lineate, with coarser lines near the middle.
Not common. Port Penn, Delaware River.
Pl. 14, Fig. 4.
AMPHIPRORA ORNATA BAIL.
Frustule membranaceous, constricted in the middle, with well-marked folds extending from the junction line in both directions. Valve lanceolate, constricted in the middle and with protracted ends. Keel undulate on the edge.
A beautiful, transparent and delicate form, the only fresh-water species in our locality.
Delaware Water Gap, Pa.
Pl. 14, Figs. 6 and 7.
AMPHIPRORA PALUDOSA WM. SM.
Frustule membranaceous, constricted, with truncate ends. Valve linear, with acute ends. Striæ scarcely visible.
Cape May (Cleve).
Pl. 14, Fig. 5.
TROPIDONEIS CLEVE (1891)
(tropis, a keel)
Frustule oblong, constricted in the middle; keel not sigmoid. Axial area not evident. Striæ very fine, punctate, in longitudinal lines.
{69}TROPIDONEIS LEPIDOPTERA (GREG.) CLEVE
Valve with straight, median excentric line. Keel unilateral, projecting above the median line in zone view; central area small. Transverse striæ finely punctate. As usually seen, the valve is inclined. According to Karsten there are two chromatophores on the connective zone, each divided into four parts, each of which contains a large oval pyrenoid.
_Amphiprora lepidoptera_ Greg.
Along the coast.
Pl. 14, Figs. 8 and 9.
AURICULA CASTRACANE (1873)
(auricula, the ear, the shape of the valve)
Frustule globose. Valve reniform or cymbiform, elevated into a keel which is not sigmoid. Median line biarcuate. Differs from Amphiprora in not having a sigmoid keel.
AURICULA MUCRONATA (H. L. SMITH) PERAGALLO
In zone view, the median line deeply bisects the longitudinal axis, ending in a mucronate central nodule. Connective zone complex. Valve very complex, with ventral margin nearly straight and raphe excentric. Central nodule near the margin, terminal nodules small. Striæ, 35-40 in 10 µ (Cleve). Chromatophore single, on the ventral part.
_Amphora mucronata_ H. L. Smith.
_Amphora (?) insecta_ Grun.
_Auricula insecta_ (Grun.) Cleve.
"A rare and very curious pelagic species" (Peragallo, Diat. Villefranche).
Prof. H. L. Smith included this form in his first century of "Species Typicæ Diatomacearum," which was issued prior to 1876, the date of publication, in Schmidt's Atlas, of Amphora insecta Grun.
Atlantic City, N. J. Rare.
Pl. 15, Fig. 2.
SCOLIOTROPIS CLEVE (1894)
(scolios, twisted, and tropis, a keel)
Frustule linear, oblong. Median line sigmoid near the ends. Valve with transverse costæ alternating with two intermediate rows of puncta in oblique lines.
SCOLIOTROPIS LATESTRIATA VAR. AMPHORA CLEVE
Valve asymmetrical, with the median line curved. Frustule sub-acute at the ends. Median lines not on the same side of each valve of the frustule.
Abundant at Cape May, N. J. Not common elsewhere.
Pl. 14, Figs. 10 and 11.
GOMPHONEIS CLEVE (1894)
(gomphos, a peg, and neis (naus))
Valve elongated, asymmetrical to the transverse axis; axial area narrow; central area rounded, stigmatic; striæ radiating, costæ alternating with double rows of fine puncta. An indistinct, longitudinal line near the border.
Chromatophores and conjugation have not been determined.
{70}GOMPHONEIS HERCULANEUM (EHR.) CL.
Valve clavate, with rounded apex; costæ, 13 in 10 µ, alternating with double rows of fine puncta, 22 in 10 µ, in oblique rows; axial area narrow, central area rounded, with one stigma.
_Gomphonema capitatum_ Ehr var. _herculaneum_ Ehr., H. L. S., Type Slide No. 177.
Common in the blue clay.
Pl. 19, Fig. 2.
Pl. 38, Fig. 15, zone view of young frustule.
GOMPHONEIS MAMILLA (EHR.) CL.
Valve lanceolate, with rounded apex and base; striæ costate, 10 in 10 µ, alternating with double rows of fine puncta; axial area linear, sometimes oblique, central area small, with one or more stigmas.
Blue clay. Rare.
Pl. 19, Fig. 1.
In one frustule I noticed one valve with one stigma and the other with four stigmas.
The difference between G. mamilla and G. elegans is not very great. In the latter the central area is larger and the longitudinal lines not so near to the margin. The stigmas form a circlet. There appears to be a coincidence in the relation of Gomphoneis to Gomphonema, and that of the true Achnanthes to the group described by Cleve under Achnanthidium. In Gomphoneis and Achnanthes the striation is both costate and punctate while in Gomphonema and Achnanthidium the striation is punctate only.
GOMPHONEMA AG. (1824)
(gomphos, a peg, and nema, a filament)
Valve elongated, asymmetrical with respect to the transverse axis; striæ transverse, usually radiate, punctate.
Chromatophore band single, the middle lying on one zone.
In conjugation, according to Thwaites and Pfitzer, from two mother cells, which do not form a positive union, two auxospores are developed parallel to the original frustules. In Plate 19, Fig. 19, I have drawn a representation of the auxospore formation as I have frequently observed it in a gathering sent me by Mr. T. C. Palmer, containing G. angustatum, a common species in this locality. The sagittal plane of the valve of the auxospore is at right angles to the plane of the valve of the mother cell. Two valves of one of the mother cells are seen separated, one on each side of the auxospore which is nearly twice the length of the original frustules. The two valves of the other mother cell are not shown as they are not usually found closely united. In the figure one valve alone of the auxospore is seen, the opposite valve not being in focus. The valves of the auxospore are usually more or less arcuate, as in Cymbella, to which the genus is closely allied.
Grunow divides Gomphonema into two groups, Asymmetricæ and Symmetricæ, according to the presence or absence of stigmas. Cleve suggests Stigmaticæ and Astigmaticæ as more suitable in order to agree with the Cymbellæ. The Stigmaticæ are found chiefly in fresh water, sometimes in brackish. All of the marine forms belong to the Astigmaticæ, which, however, include some common fresh-water forms. Many species of Gomphonema are stipitate, some occur in gelatinous masses, and others are free.
{71}GOMPHONEMA MONTANUM SCHUM.