Part 46

The _flower_ has =5= sepals (the median, as usual, posterior), =5= petals, =5= stamens and =2= carpels (in the median line) (Fig. 528). The calyx is often scarcely indicated. The petals have a short claw are most frequently obcordate, or have an incurved apex (Fig. 528 _B_, _C_), being incurved in the bud; they are white, rarely yellow (Fennel and Parsnips), blue or red. The flowers are sometimes zygomorphic, especially those on the circumference of the umbel, and in that case it is the petal which is directed outside (anterior) which is the largest, and the two posterior are the smallest (_e.g. Heracleum_). The stamens are _incurved_ in the bud. The 2 _free styles_ unite at the base into the “stylar-foot” (_stylopod_), a swollen nectary (Fig. 528 _B_, _C_); the ovary is bilocular, the raphe of the ovules being directed inwards. _The fruit is a schizocarp_, _dividing into two mericarps_; the plane in which these separate coincides with that of the union of the carpels, and the two _nut-like mericarps_ are in most genera kept together for awhile at the top of a thin, bifid, or undivided stalk (_carpophore_) which is in direct continuation with the flower-stalk (Fig. 537). Each mericarp has most frequently 5 more or less strongly projecting ridges, the _primary ridges_ (Figs. 530, 532, 534, 535, etc.), of which 3 lie on the back of the mericarp, the _dorsal ridges_, and 2 on its edge near the plane of division, the _marginal ridges_; five of these (10 ridges in all in the entire fruit) are placed opposite the calyx-teeth and the others between them. In some genera there are in addition 4 _secondary ridges_ to each mericarp between the primary ones (Fig. 528 _E_: the secondary ridges bear the long bristles). Inside these secondary ridges, or inside the grooves between the primary ridges, when the secondary ridges are absent, _oil ducts_ (vittæ, schizogenous ducts) are found in the pericarp, most frequently one in each groove; two are also often found on the ventral side of each mericarp (Figs. 528 _E_, 530 _ol_, etc.). The seed is most frequently united with the pericarp. The _embryo_ is _small_ and lies high up in the large, most frequently horny endosperm (Fig. 528 _D_).--The endosperm _does not contain starch, but oil_, and presents three different forms, of important systematic value: (=a=) those which are quite flat on the ventral side (_i.e._ the side turned towards the plane of splitting) (Figs. 528 _E_, 530, 531, 534, etc.): the majority of the genera, ORTHOSPERMEÆ (_e.g._ _Carum_, _Pastinaca_); (=b=) those in which the endosperm on the ventral side is provided with a longitudinal groove, often deep: CAMPYLOSPERMEÆ (_e.g._ _Anthriscus_); the transverse section is nearly a crescent (Fig. 532); (=c=) those in which the endosperm is concave on the ventral side (hollow in both longitudinal and transverse sections): CŒLOSPERMEÆ (_e.g._ _Coriandrum_) (Fig. 538).

The genera are distinguished first of all by the endosperm and forms of fruit, the ridges and oil-ducts; then by the form of the umbel, the calyx and corolla, by the absence or presence of an involucre, etc.

1. HYDROCOTYLEÆ, PENNY-WORT GROUP. _Capitula_ or _simple umbels_ (all the other groups have compound umbels). No oil-ducts. Orthospermous.--_Hydrocotyle_ (Penny-wort). The fruit is _considerably compressed_ laterally (Fig. 529). The calyx-teeth are small. The leaves are peltate.--_Didiscus._--_Sanicula_ (Sannicle). The umbels are small, capitate, generally collected in a raceme; calyx-teeth distinct. ♂-and ♀-flowers in the same umbel. The fruits are round, studded with hooked bristles. No carpophore.--_Astrantia_ has an umbel surrounded by a large, often coloured involucre, with this exception it is the same as the preceding, but the fruit is slightly compressed, with 5 equal ridges. _Hacquetia_ (_Dondia_).--_Eryngium_ (Sea Holly): leaves often thorny. The flowers _are all sessile_, the inflorescence is thus a capitulum; each flower is often subtended by a bract, which is thorny like the involucre, resembling the burrs of the Teasel. The sepals are large.--~_Lagœcia_: one of the loculi of the ovary is suppressed.~

=2.= AMMIEÆ, CARAWAY GROUP (Figs. 530–532). The fruit has only the 10 primary ridges; it is usually short, almost spherical or broadly ovate and distinctly _compressed_ laterally. Oil-canals are most frequently present. Orthospermous (except _Conium_).--_Cicuta_ (Cow-bane). Pointed calyx-teeth. Glabrous herbs with pinnate or bipinnate leaves. ~_C. virosa_ has a thick, vertical rhizome, divided by transverse septa into many compartments; the leaflets are narrow, lanceolate, and dentate; the large involucre is wanting.~--_Apium_ (Celery). No calyx-teeth. _A. graveolens_, a maritime plant, has neither large nor small involucre; the umbels are short-stalked or sessile.--_Carum_ (Caraway). Calyx-teeth small; the large involucre is wanting or is only few-leaved. _C. carvi_ (Caraway). _C. petroselinum_, (Parsley) (Fig. 530). _Falcaria_; _Ammi_; _Helosciadium_; _Bupleurum_ (Hare’s-ear) with simple leaves and yellow corolla; _Pimpinella_ (Fig. 531); _Sium_; _Ægopodium_ (_A. podagraria_, Gout-weed) has bi- or tri-ternate leaves, with ovate, dentate leaflets; the large involucre is wanting.--_Conium_ is campylospermous (Fig. 532); the short, broadly ovate fruit has distinctly projecting, often wavy crenulate ridges. _C. maculatum_ (Hemlock) has a round, smooth stem with purplish spots.

=3.= SCANDICEÆ. This group has a distinctly oblong or linear fruit which is _slightly compressed laterally_, and generally prolonged upwards into a “beak”; wings absent. _Campylospermous._ Otherwise as in the Ammieæ.--_Anthriscus_ (Beaked Parsley) has a lanceolate fruit, round on the dorsal side, without ridges, but with a ten-ridged beak.--_Scandix_ (Shepherd’s-needle).--_Chærophyllum_ (Chervil): fruit lanceolate or linear with low, blunt ridges; beak absent or very short. _C. temulum_ has a red-spotted, hairy stem.--_Myrrhis_ (Cicely) has a short beak and sharp, almost winged ridges. _M. odorata_ (Sweet Cicely) has very long fruits.

=4.= SESELINEÆ, FENNEL GROUP (Figs. 533, 534). The fruit is slightly elliptical or oblong, in transverse section circular or nearly so, without grooves in the dividing plane; only primary ridges are present. Orthospermous.--_Fœniculum_ (Fennel) has yellow petals; both involucres are wanting; the fruit is oblong. The ridges are thick, all equally developed, or the lateral ridges are slightly larger (Fig. 534).--_Æthusa_ (_A. cynapium_, Fool’s Parsley); the large involucre is wanting or is reduced to one leaf, the small involucre is composed of three linear leaves which hang downwards on the outer side of the umbels. The fruit is spherical-ovate, with thick, sharp, keeled ridges, the lateral ones of which are the broadest.--_Œnanthe_ (Dropwort); the fruit (Fig. 533) has usually an ovate, lanceolate form, with distinct, pointed sepals and long, erect styles; the ridges are very blunt, the marginal ones a trifle broader than the others.--_Seseli_, _Libanotis_, _Cnidium_, _Silex_, _Silaus_, _Meum_, etc.

=5.= PEUCEDANEÆ, PARSNIP GROUP (Figs. 535–537). The fruit is most frequently very strongly _compressed_ dorsally, with broad, mostly _winged_, lateral ridges. Only primary ridges. The dorsal ridges may project considerably, but are not winged. Orthospermous.

=a.= The winged lateral ridges stand _out from each other_, so that the fruit appears to be 4-winged (Fig. 535).--_Angelica_; _Archangelica_ (Fig. 535); _Levisticum_ (Lovage).

=b.= The winged lateral ridges lie _close together_, and form one wing on each side of the fruit (Fig. 536).--_Pastinaca_ (Parsnip). Corolla yellow. The dorsal ridges are very weak; the oil-ducts do not reach quite as far as the base of the fruit. Both large and small involucres are wanting; leaflets ovate. _Anethum_ (Dill) is a Parsnip with more distinct dorsal ridges and filamentous leaflets. _Peucedanum_ (Hog’s-fennel); _Ferula_ (with _Scorodosma_, Fig. 536, and _Narthex_); _Dorema_.--_Heracleum_ (Cow-parsnip); the flowers in the margin of the umbels are often very large, zygomorphic, and project like rays, _e.g._ in _H. sibiricum_. The fruit is very flat, with very small dorsal ridges; the oil-ducts are more or less club-like and _do not reach as far as_ the base of the fruit (Fig. 537). _Imperatoria_; _Tordylium_.

=6.= DAUCEÆ, CARROT GROUP (Fig. 528). The fruit has 18 ridges, _i.e._ each fruitlet has 5 primary and 4 secondary ridges, the latter being often more prominent and projecting further than the primary ones. The oil-ducts are situated under the secondary ridges (Fig. 528).

=a.= ORTHOSPERMOUS: _Daucus_ (Carrot). The secondary ridges project much further than the primary, and bear on their crests a series of hooked spines (Fig. 528 _D_, _E_); these are much longer than the small bristles on the primary ridges. ~The involucral leaves of _D. carota_ (Carrot) are numerous and deeply pinnate; the inflorescence contracts during the ripening of the fruit, and since the external umbels have longer stalks than the central ones, they arch over them, and the inflorescence becomes hollow. For the terminal flower, see below.~--_Cuminum_; _Laserpitium_; _Melanoselinum_.

=b.= CAMPYLOSPERMOUS: _Torilis_ (Hedge Parsley). The primary ridges are covered with bristles; the secondary ridges are not. very distinct on account of the spines, which entirely fill up the grooves. _Caucalis_ (Bur Parsley).

=c.= CŒLOSPERMOUS: _Coriandrum_ (Coriander) has a smooth, spherical fruit (Fig. 538) with a distinct, 5-dentate calyx, the two anterior (_i.e._ turned outward) teeth being generally longer than the others; the two fruitlets scarcely separate from each other naturally; all the ridges project only very slightly, the curved primary ones least, the secondary ridges most.

POLLINATION. The flowers are adapted for insect-pollination; they secrete nectar at the base of the styles; individually they are rather small and insignificant, but yet are rendered conspicuous by being always crowded in many-flowered inflorescences. _Protandry_ is common, sometimes to such an extent that the stamens have already fallen off before the styles begin to develop (Fig 539, 2). Insect visits are more frequent and numerous as the inflorescences are more conspicuous. The flowers as a rule are ☿, but ♂-flowers are often found interspersed among the others (Fig. 539), and the number of these becomes greater on the umbels developed at the latest period. A terminal flower, which differs from the others in form, and in _Daucus carota_ often in colour also (purple), is sometimes found in the umbel. The nectar lies so exposed and flat that the flowers are principally visited by insects with short probosces, especially Diptera; bees are less frequent visitors, and butterflies rare.--1400 species (175 genera); especially from temperate climates in Europe, Asia, N. Am. About 68 species in this country.

USES. A few are cultivated as ornamental plants. They are, however, useful in medicine,[38] and for culinary purposes on account of the _essential oils_ and _gum-resins_ which in many are formed in root, stem, and fruit. The FRUITS of the following are used: _Carum carvi_ [+] (Caraway), _Carum petroselinum_ (Parsley; also the leaves and root; its home is the Eastern Mediterranean); _Fœniculum capillaceum_ [+] (Fennel; S. Europe); _Pimpinella anisum_ [+] (Anise; E. Mediterranean); _Coriandrum sativum_ [+] (Coriander; S. Eur.); _Œnanthe phellandrium_ (Water Dropwort); _Cuminum cyminum_ (Point Caraway; Africa; cultivated in S. Europe); _Anethum graveolens_ (Dill). The LEAVES of the following are used as pot-herbs: _Anthriscus cerefolium_ (Chervil); _Myrrhis odorata_ (Sweet Cicely; Orient.); _Conium maculatum_ [+] (the green portions; Hemlock). Besides Parsley, the ROOTS of the following are used: Carrot, Parsnip, _Sium sisarum_ (Sugar-root; E. Asia); _Chærophyllum bulbosum_ (Chervil-root); _Levisticum officinale_ (foliage-shoots; S. Europe); _Imperatoria ostruthium_; _Apium graveolens_ (Celery, the root in conjunction with the internodes); _Pimpinella saxifraga_ and _magna_ (Pimpinell); _Archangelica_ (Angelica, the root of _A. norvegica_ was formerly an article of food in Norway). _Poisonous alkaloids_ are found in a few, such as Fool’s Parsley (_Æthusa cynapium_), Hemlock (_Conium maculatum_), Cow-bane (_Cicuta virosa_) and species of _Œnanthe_.--_Gum-resin_ is extracted from various species: “Galbanum” from _Ferula galbaniflua_ [+] and _rubricalis_ [+] (Persia); Asafœtida from _Ferula scorodosma_ [+] and _F. narthex_ [+]; Ammoniac-gum from _Dorema ammoniacum_ [+], all from Central and S. W. Asia. “_Silphium_” was an Umbelliferous plant which grew in ancient times in Cyrene, and from which the Romans extracted a valued condiment.

Family 25. =Hysterophyta.=

This family (with the exception of Aristolochiaceæ) includes only parasitic plants. Partly on this ground, and partly because they all have _epigynous_ flowers, they are considered to belong to the youngest type (which is expressed in the name ὕστερος, the one that comes after). It is not certain to which of the preceding families they are most nearly allied. ~Again, it is a matter of doubt whether the Aristolochiaceæ are related to the others; they are by Engler united with Rafflesiaceæ into one family, _Aristolochiales_.~

Order 1. _Aristolochiaceæ._ The majority are perennial herbs or twining shrubs, whose stalked, simple, and generally more or less cordate or reniform leaves are borne in 2 rows and are exstipulate. The flowers are _hermaphrodite_, _epigynous_, regular or zygomorphic; perianth-leaves united, _simple_ but most frequently _petaloid_ and 3-merous; 6 or 12 (in _Thottea_ as many as 36) stamens with _extrorse_ anthers. The ovary is more or less completely 4–6-locular with ovules attached in the inner angles of the loculi (Fig. 540 _kf_). The style is short, and has a large, radiating stigma (Fig. 540 _n_). Fruit a capsule. Seeds rich in endosperm.

_Asarum europæum._ Each shoot has 2 reniform foliage-leaves, between which the terminal flower is borne (the rhizome becomes a sympodium by development of the bud in the axil of the upper foliage-leaf). The flower is _regular_ and has a bell-shaped perianth with 3 outer valvate, and 3 inner small segments (which may be wanting). =12= (2 × 6) free, extrorse stamens, 6 carpels.--_Aristolochia clematitis_ (Birth-wort) has an erect, unbranched stem, bearing many flowers in the leaf-axils, in a zig-zag row (accessory buds in a unipared scorpioid cyme). The flowers are zygomorphic (Fig. 540), formed by 3 alternating, 6-merous whorls. The perianth has a lower, much-distended part (_k_), succeeded by a narrow, bent tube (_r_), which passes over into an oblique, almost tongue-like projection (6 vascular bundles indicate that the number 6 is prevalent here, as in _Asarum_); =6= stamens (Fig. 540 _a_), with the dorsal portion turned upwards, are united with the short style to form a _stylar column_; they are placed quite beneath the 6 commissural stigmatic rays, which arch over them as short, thick lobes. ~Protogynous; POLLINATION is effected in _Arist. clematitis_ by small flies; these enter the erect unfertilised flower through the tube (Fig. 540 _A_, _l_) without being prevented by the stiff, downwardly-turned hairs which line the tube and prevent their escape; they find the stigma (_n_) fully developed, and may pollinate it with the pollen they have brought with them. The stigmas then straighten and wither (_B_, _n_), the anthers open, and the flies may again be covered with pollen; but the hairs which blocked up the tube do not wither until the anthers have shed their pollen, and only then allow the imprisoned flies to escape and effect cross-pollination. Prior to pollination, the flowers stand erect, but after this has taken place they become pendulous, and the perianth soon withers.--_A. sipho_ (Pipe-flower), another species, is a climber, and often grown in gardens; it has only one row of accessory buds in the leaf-axils.--200 species; chiefly in S. Am. OFFICINAL: the rhizome of _Aristolochia serpentaria_ (N. Am.).~

Order 2. =Santalaceæ.= Parasites containing chlorophyll, which, by the help of peculiar organs of suction (haustoria) on their roots, live principally on the roots of other plants. Some are herbs, others under-shrubs. The regular, most frequently ☿-flowers have a simple perianth, which is gamophyllous, 3- or 5 partite with the segments valvate in the bud, and a corresponding number of stamens opposite the perianth-leaves. In the inferior ovary there is a _free, centrally placed_, often long and curved _placenta_ with three ovules (one opposite each carpel); these are naked, or in any case have an extremely insignificant integument. Fruit a nut or drupe. Seed without testa. Endosperm fleshy. 225 species; chiefly in the Tropics.--_Thesium_, a native, is a herb with scattered, linear leaves and small 5-merous flowers (P5, A5, G3) in erect racemes; the subtending bracts are displaced on the flower-stalks. Fruit a nut.--_Osyris_ (diœcious shrub; 3-merous flowers) is another European genus.--_Santalum album_, which grows in E. Ind., yields the valuable, scented Sandalwood, the oil of which is used medicinally.--_Quinchamalium._

_Myzodendron_ is a reduced form of the Santalaceæ; the ♂-flowers are without perianth; the perianth of the ♀-flower is 3-merous. About 7 species; S. Am.; parasitic on a Beech (_Nothofagus_). The fruit has 3 feathery brushes, alternating with the lobes of the stigma, which serve as flying organs and to attach the fruits to a branch (Fig. 541), the brushes twining round as soon as they come in contact with it. There is only 1 seed in the fruit, which germinates by a long, negatively heliotropic hypocotyl, and is attached by a radicle modified into an haustorium.

Order 3. =Loranthaceæ= (=Mistletoes=). Plants containing chlorophyll which are parasites on trees, and most frequently have opposite, simple, entire leaves and regular, epigynous, often unisexual, 2- or 3-merous flowers, with single or double perianth. Stamens equal in number and opposite to the perianth-leaves, free, or in varying degrees united to one another. The inferior ovary is constructed as in the Santalaceæ, the ovules being situated on a low, free, centrally-placed placenta, but the placenta and ovules unite with the wall of the ovary into _one connected, parenchymatous mass_, in which _the embryo-sacs are imbedded_. Only 1 (less frequently 2–3) of the 1–6 embryo-sacs is fertile. The number of the carpels however varies. The fruit is a _1-seeded berry_, whose inner layer is changed into a _tough slimy mass_ (bird-lime), which serves to attach the fruits to other plants.

The two groups, _Loranthoideæ_ and _Viscoideæ_, are distinguished by the fact that the former has a distinct “calyculus,” _i.e._ an entire or lobed, or dentate swelling on the receptacle below the perianth. The majority of the Loranthoideæ have a petaloid perianth; in all the Viscoideæ, on the other hand, it is sepaloid.