A Handbook of Systematic Botany, by Dr. E Warming

Only a few Grasses have a solid stem, such as Maize, Sugar-cane, and Andropogon. The blade is flat in the meadow-grasses, but the Grasses which live on dry places (“prairie-grass”) exposed to the sun, often have the blade tightly rolled up and almost filiform or bristle-like, with anomalous anatomical structure. A closed tubular sheath is found in Melica uniflora, Bromus-species, Poa pratensis and trivialis, Briza and some Glyceria-species. The sheath is developed for the purpose of supporting the young internodes while their growth is proceeding at the base. The “nodes” (the swollen joints which are seen on stems of Grasses) are not really part of the stem but are formed by the base of the leaf-sheath. They play a part in assisting the haulms to regain a vertical position when laid prostrate by wind or rain. The awn on the pale is homologous with the blade of the Grass-leaf, and the pale itself is the sheath. The arrangement of the leaves in the spikelet is similar to that in Cyperus and other Cyperaceæ, their floral-leaves being borne in several rows in Streptochæta. More than two barren “glumes” are found in Streptochæta, several Phalarideæ and others. The spikelets, too, are again arranged in two rows in the axils of suppressed floral-leaves. The inflorescence becomes a “compound spike” (ear) when the spikelets are sessile. In the majority of instances the spikelets are borne on long stalks; when these branch, then the secondary branches, and similarly all branches of higher order, are placed so far down upon the mother-axis that they all appear to be of equal value and to arise in a semicircle from the mother-axis itself, though in reality they arise from each other (Panicle, Fig. 288 A). Sometimes the main axis and branches of different orders unite together as in Alopecurus, Phleum, and some other Grasses, and hence the single (short-stalked) spikelets appear to arise singly and spirally, or without any definite order, directly from the main axis, with the production of a cylindrical inflorescence bearing “spikes” on all sides, that is, a “spike-like panicle.”—Many inflorescences are somewhat dorsiventral. The flower is rarely unisexual (Zea mais) or barren. Considerable difficulty is experienced in reducing the Grass-flower to the ordinary 3-merous Monocotyledonous type. Some authorities consider the lodicules, which are present in all Grasses but absent in the Cyperaceæ, to be homologous with a perianth. According to a more recent theory they are bracteoles, and hence the Gramineæ, like many of the Juncaceæ, have 2–3 bracteoles placed in two rows in the median plane. If this theory be correct, the flower is naked. The lodicules expand quickly and cause the opening of the flower (i.e. the two pales become separated from each other). Generally only 3 stamens belonging to the outer whorl are present (Fig. 290), as in Iris (Fig. 279), certain Juncaceæ and Cyperaceæ (Fig. 284), but in some, such as the Rice and certain species of Bamboos, all 6 are found. Pariana has more than 6. Only 1 of the carpels is present, namely, the anterior (of those in Fig. 284), so that the ventral suture and the place of attachment of the ovule are situated at the back of the ovary. The number of styles does not correspond with the number of carpels, and the styles may therefore be supposed to arise from the edges of the leaf to the right and left—a position which is not without analogy. In addition, a stylar projection is sometimes found on the anterior side and in the median line (e.g. in Phragmites), and the solitary style in Nardus has exactly this position; a similar arrangement is found in some species of Bambusa which have only one style; other species of Bambusa have three styles. A tripartite style is found in Pharus.

[The Grass-flower may be reduced to the ordinary Monocotyledonous type thus:—The outer pale is the bract of the flower since it bears in its axil the floral shoot; the inner pale occupies the customary position of the bracteole. The fact that it is binerved can be explained by its having been pressed against the main-axis during development. Similar binerved bracteoles are found in Iris (Fig. 279). These bracteoles in both Grass and Iris arise from single primordia, and are not produced by the coalescence of two leaves. The lodicules are the only parts of the perianth remaining, the outer whorl having been suppressed, and also the posterior leaf of the inner whorl; a posterior lodicule, however, is found in the Rice and some species of Bamboo. The outer whorl of stamens is usually absent, though this again is present in the Rice and Bamboo. The three carpels are reduced to one with two or sometimes three stigmas.]

The Flowering. In the panicles the flowers open in basipetal order; the flowers in the spikes situated somewhat above the middle, commence to open first, and the flowering proceeds upwards and downwards. A few Grass-flowers never open (cleistogamic); Leersia oryzoides, Stipa-species, and e.g. Wheat and Rye in cold damp weather; some open their pales so wide that the anthers and stigmas may protrude at the top; most frequently the lodicules expand and force the pales suddenly and widely apart. The filaments elongate considerably, so that the anthers are pendulous and the stigmas unfold. In some Grasses e.g. Wheat, the blooming of each flower only lasts a short time. Pollination is generally effected by the wind. The Rye separates the pales very widely in the morning, and allows the anthers and stigmas to appear; it is almost entirely sterile when self-pollinated. The Wheat flowers at any time of the day, each flower lasting only a quarter of an hour. The pales open suddenly, but only half way, and the anthers scatter one-third of the pollen in their own flower and two-thirds outside. Self-pollination is effectual, but crossing gives better results. In Hordeum vulgare (all flowers ☿) the flowers of the 4 outer rows behave as in the Wheat, but those in the two central rows always remain closed. The ☿-flowers in the two central rows of H. distichum remain closed and fertilise themselves; they open exceptionally, and may be pollinated by the ♂-flowers in the 4 lateral rows. H. hexastichum is cleistogamic. Oats pollinate themselves.

The ripe Grass-fruit, in some species of Bamboo, is a berry; in some other Grasses a nut with loosely lying seed, in some even a capsule, but otherwise a “caryopsis.” In some instances it is loosely enveloped by the pales (Oat), in others firmly attached to these (Barley), and finally, in others, “naked,” i.e. it is entirely free from the pales (Wheat and Rye). On the ventral side there is a groove (Fig. 288 E); on the anterior side (dorsal suture), which is turned towards the inner pale, it is convex, and at the base on this side, inside the testa, lies the embryo (Fig. 288 D). The apex of the fruit is often hairy (Fig. 293). The skin (Fig. 291, a) is formed by the pericarp and testa, and in some cases (Barley) the pales also form the outer portion. The endosperm (b) is large, and formed of parenchymatous, starch-containing cells: aleurone (proteid) grains may also be found among them. When the starch-grains and the aleurone-grains adhere together the endosperm becomes “horny,” but is “floury” when the starch-grains lie loosely with air between them. In the most external region, just beneath the skin, 1–several layers of nearly cubical cells (filled principally with aleurone-grains and fat) are found, the aleurone-layer (Fig. 292). The embryo (Fig. 291 c-d) contains large quantities of fatty oil; the large shield-like structure, attached to the embryo and turned inwards towards the endosperm (c), is the cotyledon (scutellum); it remains enclosed in the seed during germination, and dissolves the endosperm by means of the peculiar epithelial cells developed on the dorsal surface. The radicle, on germination, is obliged to perforate a mass of cells derived from the suspensor and which form the “root-sheath” (coleorhiza, Fig. 293) round its base. In addition to the tap-root, lateral roots are frequently developed before germination; these quickly break through, and later on are followed by others which appear at the base of the leaf (Figs. 293, 294).

The DISTRIBUTION OF THE FRUIT is most frequently effected by the wind. The spirally-twisted and hygroscopic awn which persists on the fruits of some species (Avena, Stipa, etc.) assists in their dissemination, and even helps to bury them in the ground.

The two preceding orders are more closely related to each other than they are to the Gramineæ.

The generic differences are chiefly founded on the form of the inflorescence, the number and sex of the flowers in the spikelets, the shape and relative length of the pales, awns, etc. In addition to these the structure of the fruit and seed presents a great many differences; some have compound starch-grains, while in others they are single; some have 1 layer of aleurone-cells, others have several (Fig. 292), etc.

1. Bambuseæ. Tall Grasses with woody, very siliceous stems which bear many branches in the axils of the leaves. 6 stamens. Bambusa (Bamboo).

2. Oryzeæ. Oryza sativa (Rice) is a herbaceous marsh-plant, with panicle and small, 1-flowered spikelets, with two small glumes and two large, boat-shaped, strongly siliceous pales. 6 stamens.—Leersia. Lygeum. Pharus. Zizania aquatica.

3. Maydeæ. Zea mais (Indian-corn, Maize); the spikelets are unisexual; the ♂-spikelets in a terminal panicle; the ♀-spikelets closely crowded and arranged in many rows in a thick, axillary spike, enclosed by large sheathing-leaves. The ♀-spikelets are 1-(2-) flowered; the ovary bears one, long, filamentous style, with bifid stigma.—Euchlæna; Coix.

4. Andropogoneæ. Saccharum (Sugar-cane); the spikelets are exceptionally small, 1-flowered, and borne in pairs in many-flowered, long-haired panicles. Tall grasses with solid, sappy stem.—Andropogon.

5. Festuceæ. Grasses with panicle (or spike-like panicle) and 2–several-flowered spikelets. Glumes small, in each case shorter than the spikelet.—Festuca (Fescue) and Bromus (Brome, Fig. 288) have the awn placed at the apex of the pale, or slightly below it. Festuca has perennial species, with only a sparsely-branched panicle with branches solitary or in pairs, and round spikelets; the leaf-sheath is widely open. Bromus has the branches borne in half whorls, and the leaf-sheath scarcely half open. Brachypodium has very short-stalked spikelets in a raceme.—Poa (Meadow-grass), Briza (Quaking-grass) and Glyceria have awnless spikelets; these in Poa are ovoid, compressed, and with sharply-keeled glumes; in Briza they are broad, cordate and drooping, with boat-shaped glumes; in Glyceria round, long, many-flowered, linear or lanceolate; some species of Glyceria have closed leaf-sheaths.—Dactylis (Cock’s-foot) differs from all others in the somewhat crowded and unilateral (subsecund) spikelets, which are compressed and oblique (i.e. one side more convex than the other).—Phragmites (P. communis, Reed); the lowermost flowers of the spikelet are ♂; its axis is covered with long, silky hairs; pales without awns, but acuminate. Perennial marsh-plants.—Melica; panicle small, sparsely-branched with round, awnless, few-flowered, usually drooping spikelets. The upper pales, with arrested flowers, are generally united into a club-like mass.—Molinia, Eragrostis, Koeleria, Catabrosa.—Cynosurus (Dog’s-tail) has a small, spicate panicle with unilateral spikelets, some of which are fertile, some barren, each supported by a pectinate scale. Arundo. Sesleria. Gynerium. Triodia.

6. Aveneæ. Panicles with 2–many-flowered spikelets; at least one of the glumes is quite as long as the entire spikelet.—Avena (Oat). The pale is boat-shaped, often bifid, and at about the middle of the back has a twisted, bent awn.—Aira (Hair-grass) has a long-branched panicle with small, 2-flowered spikelets; the pale has a dentate apex and bears an awn on the posterior side close to the base.—Weingærtneria.—Holcus (Yorkshire-fog); a soft, hairy Grass with an open panicle, keeled glumes; 2 flowers in the spikelet, of which the lower one is ☿, the upper ♂; the pale which supports the ☿-flower has no awn, but that which supports the ♂-flower, on the contrary, is awned.

7. Agrostideæ. Panicles or spike-like panicles with 1-flowered spikelets. Generally 2 glumes and only 1 pale.—The following have PANICLES: Milium with square panicle-branches and round spikelets; Agrostis (Fiorin), with compressed, glabrous spikelets, whose glumes are longer than the pales. Calamagrostis differs in having a chaplet of long hairs at the base of the pale.—Stipa (Feather-grass) has a long, twisted awn.—The following have SPIKELIKE PANICLES: Phleum (Cat’s-tail, Timothy-grass) has sharply pointed, entirely free glumes, which are much longer than the awnless pales. Alopecurus (Fox-tail); glumes united below; pale with awn. Ammophila (Psamma). A. arundinacea; pales hairy at base; perennial, stiff-leaved, glaucous sand-grass with creeping rhizome. Aristida. Sporobolus.

8. Phalarideæ. Panicles and spike-like panicles. The spikelet has in the upper part a single fertile flower; below it are placed 4 pales, of which the upper 1–2 sometimes support ♂-flowers. On the whole, 6 floral-leaves of the first order are present.—Phalaris (P. canariensis, Canary-grass) has an ovate, spike-like panicle, the spikelets are compressed, convex on the outer side, concave on the inner. The large glumes are winged on the back.—Digraphis (D. arundinacea) is closely allied to Phalaris, but the keel of the glumes is not winged.—Anthoxanthum (A. odoratum, Sweet-vernal) has a small, lanceolate, open, spike-like panicle; the spikelets have below 2 barren flowers, and above these an ☿-flower with 2 stamens. The upper glume is longer than the flower.—Hierochloa.

9. Chlorideæ. The spikelets are arranged in the form of a spike in two rows on one side of an often flatly-compressed axis; they are mostly 1-flowered.—Chloris; Ctenium; Cynodon; Eleusine; Microchloa.

10. Paniceæ. The spikelets are borne in panicles or spikes, which may be arranged like fingers or in a raceme. There is a centrally-placed ☿-flower; below it is sometimes a ♂-flower.—Panicum; Paspalum; Oplismenus; Setaria has an almost cylindrical spike-like panicle with several barren branchlets, which project as stiff, rough bristles.—Cenchrus; Pennisetum.

11. Hordeæ. Spikes compound; spikelets sessile in the notches of a toothed axis.

A. Spikelets solitary.—Triticum (Wheat, Fig. 287) has in each tooth of the main axis, a several-flowered spikelet which turns its flat side towards the central axis. The cultivated species (true Wheat) are 1-2-annual, the wild ones (T. repens, Couch, also as an independent genus, Agropyrum) are perennial, with creeping rhizome and lanceolate glumes.—Lolium (Rye-grass) has in each tooth of the main axis a many-flowered, compressed spikelet, which is placed edgewise towards it and (with the exception of L. perenne) has only one outwardly-turned glume (L. temulentum has a rudiment of the inwardly-turned lower glume); the terminal spikelet has two glumes.—Secale (Rye). A two-flowered spikelet in each tooth; small, lanceolate, acuminate glumes. Nardus and Lepturus have very narrow spikes, the former with unilateral spikelets.

B. In each notch of the axis 2 or more spikelets are placed close together.—Hordeum (Barley). In each tooth three 1-flowered spikelets. H. hexastichum (6-rowed Barley), has 6 rows of fruits, since all the spikelets are fertile, and H. distichum (2-rowed Barley) 2 rows, since the lateral spikelets are (♂, and barren (p. 292).—Elymus has 2–6 many-flowered spikelets in each joint of the main axis. Ægilops has awns upon the glumes.

Distribution. 315 genera with 3,500 species. The order is distributed over the whole world, and as regards number of individuals is perhaps the richest. In the Tropics, large, broad-leaved, tree-like forms are found (Bambuseæ, Olyreæ, Andropogoneæ, etc.; in S. Europe, Arundo donax); in England, next to the Compositæ, it is the order most rich in species (about 134).—The origin of some of the cultivated Grasses is lost in obscurity. The Maize, no doubt, was indigenous to America, where its nearest relatives are found, and where it has also been discovered in ancient Indian graves; Durra or Guinea-corn, Millet and Sugar-cane are South Asiatic plants, and our own cereals no doubt have sprung primarily from Western Asia and South-Eastern Europe (Barley from Armenia and Persia, where a very closely related wild species is found; Wheat from the same districts; Rye from the perennial species S. montanum). Panicum altissimum and Rice have come from Africa.

Uses. The Grasses play a very important part as cereals and fodder plants. The following are the most important of the cultivated ones: Triticum vulgare (common Wheat), turgidum, amyleum, polonicum, spelta, durum, etc.; Secale cereale (Rye); Barley (Hordeum-species, see under the genus); Maize; Oats (Avena sativa, orientalis, nuda); Millet (Panicum miliaceum); Durra (Turkish Millet, or Guinea-corn, Sorghum vulgare, cernuum and saccharatum); Manna-grass (Glyceria fluitans). As fodder-plants especially: Rye-grass (Lolium perenne); Oat-grass (Avena elatior); Timothy (Phleum pratense); Fox-tail (Alopecurus pratensis); Cock’s foot (Dactylis glomerata); Dog’s tail (Cynosurus cristatus); Sweet-vernal (Anthoxanthum odoratum); Soft grass, or Yorkshire-fog (Holcus lanatus and mollis); Quaking-grass (Briza media); species of Meadow-grass (Poa); Fescue (Festuca) and Brome (Bromus).—Several cultivated species of Grass are also used in the preparation of fermented liquors, the starch in the seeds being transformed to sugar (beer from “Malt,” i.e. the germinated Barley; arrack from Rice); or the stem becomes specially saccharine before flowering: the Sugar-cane, Sorghum saccharatum.

Officinal. The rhizome of Triticum repens, Oat-grain, flour of Barley, and the starch of Wheat, also sugar.

The seeds of Lolium temulentum are considered poisonous.—The stems of many species (including our common grains) are used in the manufacture of paper, especially “Esparto grass” (Stipa tenacissima) from Spain and N. Africa, and the sheathing-leaves of the ♀-spike of Maize. Sand Lyme-grass (Elymus arenarius), and especially Psamma arenaria, are important.—But few Grass-species are sweet-scented: Anthoxanthum odoratum and Hierochloa odorata contain coumarin; Andropogon-species have essential oils (“Citronella oil”).—Ornamental plants are: the “Ribbon-grass” (a variety of Digraphis arundinacea), Stipa pennata (whose awn is exceedingly long and feathery), Gynerium argenteum (Pampas-grass), Lagurus ovatus, Hordeum jubatum, Bromus briziformis.

Family 3. Spadicifloræ.

The primitive form resembles that of the preceding family. In it we find the typical, perfectly developed, Monocotyledonous flower, sometimes even with free carpels and with a dry or somewhat fleshy, but never petaloid perianth; and this passes over into very different forms by the suppression of the floral-leaves, perianth and sporophylls (unisexual flowers are common), and by the close aggregation of the flowers in the inflorescence. The flower is hypogynous in every case. The inflorescence is a spike which may be either single or branched, and has often a thick and fleshy axis (a spadix). In Palms and Araceæ it is enveloped, at any rate prior to the opening of the flowers, by a very large floral-leaf, the spathe, which may be petaloid (Figs. 297, 301).

The fruit is most frequently fleshy (berry, drupe) or a nut, never a capsule. The embryo is small, with large, fleshy endosperm (Fig. 299 C); very rarely the endosperm is wanting.

The numerous plants belonging to this family are large, herbaceous or tree-like, and the leaves seldom have the usual Monocotyledonous form, i.e. linear with parallel venation, but most frequently have pinnate or palmate venation.

Order 1. Palmæ (Palms). The majority are trees with an unbranched, cylindrical stem, having short internodes and covered with leaf-scars or the bases of the leaf-stalks (Fig. 296), and at the summit a rosette of large leaves closely packed together (Fig. 295). An exception to this is found in Calamus (Cane, “Rotang”), whose thin, creeping or climbing stems have long internodes; sparsely[28] branched is, e.g. the African Doum-palm (Hyphæne). Notwithstanding their often enormous stems the Palms have fibrous roots, like the bulbous Monocotyledons. The leaves are pinnate (Feather-palms, Fig. 298) or palmate (Fan-palms, Fig. 295) and often very large; they have a well-developed petiole with an amplexicaul sheath, which is often more or less separated into a large number of fibres. In the bud the blade is entire but folded, as the leaf expands the lines of folding are torn, either those which are turned upwards (thus ∨ ∨ ∨ ∨, e.g. Pritchardia, Livistona, Phœnix, Chamærops) or those turned downwards (thus ∧ ∧ ∧ ∧, e.g. Cocos, Chamædorea, Calamus). The inflorescence is usually lateral; when, as in Sago-palm (Metroxylon rumphii) or Talipot (Corypha umbraculifera) it is terminal, the plant is monocarpic, and dies after flowering; it is often a very large and branched spadix with numerous flowers either borne externally or embedded in it, and enclosed either in one woody, boat-shaped spathe (Fig. 297) or several spathes, in the latter case one for each branch. The flowers are sessile or even embedded, regular, generally unisexual (monœcious or diœcious) with the usual diagram (Fig. 278); the perianth is inconspicuous, green or yellow, persistent, and more or less leathery or fleshy. 6, rarely 3 or many stamens. The 3 carpels remain either distinct or form one, generally 3-locular, ovary. The style is short. There is one ovule in each carpel. Often during ripening 2 carpels with their ovules are aborted. The fruit is a berry, drupe or nut, generally one-seeded, with a large horny or bony endosperm with hard thick-walled cells (e.g. Date-palm). In some (e.g. Cocoanut) it is thin-walled, soft, and oily; in several “ruminate.”

When germination commences in the Cocoanut, Date, etc., the apex of the cotyledon remains in the seed and developes into a spongy mass to withdraw the endosperm; in the Cocoanut it attains a considerable size (Fig. 299 C) and assumes the form of the fruit. The endosperm in the Cocoanut is hollow and the interior is filled with “milk.” In the Date-palm and the Vegetable-ivory (Phytelephas) the cell-walls of the hard endosperm serve as reserve material.

1. Phœniceæ. Phœnix (Date-palm) has pinnate leaves with channeled leaflets and diœcious flowers with 8 free carpels, of which usually only one developes into a berry with membranous endocarp; the large seed has a deep furrow on the inner side, and horny endosperm.

2. Sabaleæ. These have fan-like leaves with channeled segments; flowers ☿ or polygamous, rarely diœcious, with 3 separate or only slightly united carpels, all of which are sometimes developed into fruits (berry or drupe, with thin stone).—Chamærops, the Dwarf-palm. The pericarp is externally fleshy, internally more fibrous, and provided with a membranous inner layer. The endosperm is ruminate (that is, the testa is several times deeply folded into the endosperm).—Sabal, Copernicia, Livistona (Fig. 298), Thrinax, Corypha, Brahea, and others.

3. Cocoineæ. With pinnate leaves. Monœcious inflorescence. The carpels are united into a 3-locular ovary. The fruit is most frequently 1-locular, only 1 of the loculi becoming developed, rarely 3-locular; it is a drupe with a large, fibrous, external layer (mesocarp) and most frequently a very hard inner layer (endocarp, stone) which has 3 germ-pores, the 2 of these, however, which correspond to the suppressed loculi are closed; internal to the third lies the small embryo (Fig. 299). Endosperm containing abundance of oil. Cocos (the Cocoanut-palm), Attalea, Elæis, Acrocomia, Bactris.

4. Lepidocaryinæ. The floral-leaves and flowers are borne in 2 rows on the spadix. The carpels are united into one 3-locular ovary; the fruit is coated by a layer of hard, shining, imbricate scales. The majority of the species are thorny, and climb by means of the thorny leaves. Some have fan-like (Mauritia), others pinnate leaves (Raphia, Calamus, Eugeissonia, Metroxylon; the stems of the latter die after the first flowering).

5. Borassinæ. Large Fan-palms without thorns, with 3-locular ovary. Drupe with separate stones. Latania and Lodoicea have many stamens; Hyphæne; Borassus (Palmyra-palm).

6. Arecineæ. The most numerous group. Feather-palms. Berry. Areca, Euterpe, Oreodoxa, Ceroxylon, Chamædorea, Geonoma, Caryota with bipinnate leaves.

7. Phytelephantinæ. Flowers with rudimentary perianth united in close capitula. Phytelephas (Vegetable-ivory). Nipa.

Distribution. About 1,100 species are known. In Europe only the Dwarf-palm (Chamærops humilis) is wild (Western Mediterranean). The Date palm (Phœnix dactylifera) belongs to North Africa and West Asia. Other African genera are Hyphæne (Doum-palm) and Elæis (E. guineensis, Oil-palm). A large majority of the genera are found in South America and in the East Indies. The following are American:—Mauritia, Acrocomia, Bactris, Chamædorea, Oreodoxa, Euterpe, Attalea, etc. Asiatic:—Metroxylon, Calamus, Areca, Borassus, Lodoicea (“Double-cocoanuts,” Seychelles) and others. The Cocoanut-palm has perhaps an American origin; all the other species of the same genus being endemic in America; it is the only Palm found on the coral islands of the Pacific Ocean, and is also the only one which is common to both hemispheres.

Uses. Palms belong to the most useful plants; they contain no poison, and are of little medicinal interest, but are largely employed in the arts and manufactures, the hard timber being adapted for many purposes on account of the hard tissue in which the vascular bundles are embedded. “Cane” is the stem of Calamus-species (from India). Sago is obtained from the pith of Metroxylon rumphii (Sago-palm, Sunda-Is., Moluccas), Mauritia flexuosa, etc. Sugar-containing sap (“palm wine”) is obtained from the American Mauritia vinifera and flexuosa, Borassus flabelliformis (Asiatic Palmyra-palm), Arenga saccharifera, etc., by cutting off the young inflorescences, or by perforating the stem before the flowering (arrack is distilled from this). Vascular strands for the manufacture of mats and brushes, etc., are obtained from the outer covering (mesocarp) of the Cocoanut, and from the detached leaf-sheaths of Attalea funifera (Brazil) (Fig. 296). Wax is yielded by the leaves of Copernicia cerifera (carnaueba-wax, Amazon region), and by the stem of Ceroxylon andicola (palm-wax, Andes); East Indian Dragon’s blood is from the fruit of Calamus draco; the young buds of many species, especially Euterpe, Cocos, Attalea, etc., are used as “cabbage.” Palm-oil is obtained from the oily mesocarp of the plum-like fruits of Elæis guineensis (W. Africa), and from the seeds, when it is largely used in the manufacture of soap. Edible Fruits from the Date-palm (Phœnix dactylifera, Arabia, Egypt, W. Africa), and the endosperm of the Cocoanut (Cocos nucifera). The seeds and the unripe fruits of the Areca-palm (Areca catechu) are chewed with the leaves of the Betelpeper, principally in Asia. Vegetable Ivory from the hard endosperm of Phytelephas macrocarpa (S. America.)—Many species are cultivated in the tropics as ornamental plants, but in this country only Chamærops humilis, Livistona australis and chinensis are generally grown. In addition to the few just mentioned, many others are of importance, but these are much the most useful.

Order 2. Cyclanthaceæ. This is a small order related to the Palms (44 species from Tropical America), with fan-like, folded leaves. The flowers are unisexual and arranged in whorls or close spirals on an unbranched spadix. Ovary unilocular, ovules numerous. To this belongs Carludovica palmata, whose leaves are used for Panama hats.

Order 3. Pandanaceæ (Screw-pines) is another small order, forming a transition to the Araceæ. The woody, (apparently) dichotomous stem is supported by a large number of aerial roots, which sometimes entirely support it when the lower portion of the stem has decayed. The leaves are closely crowded together, and arranged on the branches in three rows, which are often obliquely displaced, with the formation of three spiral lines; they are, as in the Bromeliaceæ, amplexicaul, long, linear, the edge and lower midrib often provided with thorns. The ♂-flowers are borne in branched, the ♀ in unbranched spadices or capitula, which resemble those of Sparganium, but have no floral-leaves. Perianth absent. The drupes or berries unite into multiple fruits.—About 80 species in the islands of the Indian Ocean.—Pandanus, Freycinetia.—Fossils perhaps in the chalk of the Harz.

Order 4. Typhaceæ. The flowers are unisexual, monœcious, and borne on a cylindrical spike or globose capitulum; ♂ inflorescences above, the ♀ below. The perianth consists of a definite number of scales (Sparganium), or in its place numerous irregularly-arranged hairs are found (Typha); in the ♂-flower there are generally three stamens; the gynœceum is formed of 1–2 carpels with 1 prolonged style; 1 pendulous ovule. The seeds are furnished with a seed-cover, which is cast off on germination.—The few species (about 20) which belong to this order are marsh plants with creeping rhizome (and hence grow in clusters); the leaves on the aerial shoots are borne in two rows, entire, very long and linear.

Sparganium (Bur-reed). The flowers are borne in globose capitula; the perianth distinct, generally consisting of 3 small scales; pistil bicarpellate. Drupe, dry and woody. The stalk of the lower ♀ capitula is sometimes united with the main axis, and consequently the capitula are situated high above their subtending-leaf.

Typha (Bulrush, Reed-mace) has a long, cylindrical, brown spike, the lower portion bearing ♀-flowers, and the upper ♂-flowers, which is divided into joints by alternate leaves. The ♀-flowers have 1 carpel. The perianth is wanting, represented by a number of fine, irregularly-placed hairs; pistil unicarpellate. Fruit a nut.

The two genera, according to some, are related to the 2nd order. In both genera native species are found. The pollination is effected by the wind, and consequently the anthers project considerably, and the stigma is large and hairy. Typha is protandrous, Sparganium protogynous. The small, fine hairs surrounding the nut of Typha assist in its distribution by the wind.—Fossil Typhas in the Tertiary.

Order 5. Araceæ (Arums). The flowers are small, and always borne without bracts or bracteoles on an unbranched, often very fleshy spike, which is enclosed by a spathe, often petaloid and coloured (Fig. 301). The fruit is a berry. Outer integument of the seed fleshy.—The leaves have generally sheath, stalk, and blade with distinctly reticulate venation; they are chiefly cordate or sagittate (Fig. 302), seldom long with parallel venation as in the other Monocotyledons (Acorus, Fig. 300). The Araceæ are quite glabrous, generally perennial herbs with tubers or rhizomes. Many have latex.—For the rest the structure of these plants varies; for example, while some have a perianth, in others it is wanting; in some the perianth-leaves are free, in others united; some have hermaphrodite flowers, but the majority unisexual (monœcious); some have free, others united stamens; the ovules are orthotropous, anatropous, or campylotropous, erect or pendulous; the ovary is 1–many-locular; some have seeds with endosperm, others without. In habit there are great differences. While some, e.g. Colocasia (Fig. 302), have a thick, more or less upright stem, with leaf-scars, but not woody, others are climbers, epiphytic, and maintain themselves firmly by means of adventitious roots, on the stems and branches of trees, or even on steep rocks, e.g. Philodendron; the cordate, penninerved leaf is the most common (Fig. 302), but various branched forms appear; the pedate leaves of Helicophyllum, Dracunculus, etc., are cymosely branched; the leaves of Monstera deliciosa, perforated by tearing, should be noticed (the vascular bundles while in the bud grow faster than the tissue between them, causing the latter to be torn, and the leaf perforated). With regard to the anatomical structure, the presence or absence of latex, raphides, resin-passages, groups of mucilage-cells should be noted. Engler makes use of these anatomical peculiarities for a scientific arrangement of the order.

A. Orontieæ, Calamus-group. ☿, hypogynous flowers of a completely formed monocotyledonous type (number in the whorls 2, 3, or 4).—Acorus (A. calamus, Sweet-flag) has a regular, 3-merous, pentacyclic flower (Fig. 300 C, D). They are marsh-plants, with creeping rhizome, triangular stem, and long, sword-like leaves (Fig. 300 A); the inflorescence is terminal, apparently lateral, being pushed to one side by the upright, sword-like spathe (Fig. 300 B).—Anthurium (Pr2+2, A2+2, G2); Pothos; Orontium (unilocular ovary with one ovule), etc.

B. Calleæ. Flowers hypogynous, naked, ☿.—Calla (C. palustris). All flowers in the spike are fertile, or the upper ones are ♂; 6–9 stamens; ovary unilocular with many basal ovules. Marsh-plants with creeping rhizome and cordate leaves.—Monstera, Rhaphidophora, etc.

C. Arineæ. Flowers monœcious, naked, ♂-flowers on the upper, ♀ on the lower part of the spadix.—Arum (Fig. 301). The spadix terminates in a naked, club-like portion (k); below this is a number of sessile bodies (rudimentary flowers), with broad bases and prolonged, pointed tips (b); underneath these are the ♂-flowers (m), each consisting only of 3–4 short stamens, which eject vermiform pollen-masses through the terminal pores; then follow, last of all, ♀-flowers (f), each of which consists of one unilocular ovary, with several ovules. Perennial herbs, tuberous, with cordate leaves.—Dracunculus; Biarum; Arisarum; Pinellia (Atherurus) ternata with leaves bearing 1–2 buds. Zantedeschia æthiopica (Richardia, Nile-lily); ♂, 2–3 stamens; ♀ with 3 staminodes, 1–5-locular ovary (S. Africa.)—In some genera sterile flowers are present between the ♂ and ♀ portions of the spadix (e.g. in Philodendron); in Ambrosinia a lateral, wing-like broadening of the axis of the spadix divides the cavity of the spathe into two chambers, the anterior containing one ♀, and the posterior 8–10 ♂-flowers in two series; in some the stamens in the single ♂-flowers unite and form a columnar “synandrium” (e.g. in Dieffenbachia, Colocasia, Alocasia, Caladium, Taccarum, Syngonium). A remarkable spadix is found in Spathicarpa; it is united for its entire length, on one side, with the spathe, and the flowers are arranged upon it in rows, the ♀ to the outside, and the ♂ in the middle (Zostera has a similar one).—Pistia similarly deviates considerably, it is a floating water-plant, with hairy, round rosettes of leaves; in it also the spathe and spadix are united; at the base a ♀-flower is borne, which consists of one unilocular ovary, and above several ♂-flowers, each composed of two united stamens.

Biology. The inflorescences are adapted for insect-pollination; they are protogynous, since the viscous, almost sessile stigmas come to maturity and wither before the pollen, which is generally dehisced by apical pores, is shed; some pollinate themselves freely by the pollen from the higher ♂-flowers falling upon the ♀-flowers below them, and in some it is conjectured that the pollination is effected by snails. The coloured spathe, and the naked end of the spadix (often coloured) of certain genera function as the coloured perianth in other orders; during flowering a very powerful smell is often emitted. Arum maculatum is worthy of notice; small flies and midges creep down into the spathe, between the sterile flowers (Fig. 301 b), which are situated where the spathe is constricted, and pointing obliquely downwards prevent the escape of the insects; in the meantime, the stigmas are in a condition to receive any pollen they may have brought with them; after pollination the stigmas wither, and exude small drops of honey as a compensation to the flies for their imprisonment; after this the anthers (m) open and shed their pollen, the sterile flowers wither, and the insects are then able to escape, and enter and pollinate other inflorescences.—In many, a rise of temperature and evolution of carbonic acid takes place during flowering; a spadix may be raised as much as 30°C. above the temperature of the surrounding air.—Again, under certain conditions, many species absorb such large quantities of water by their roots that water is forced out in drops from the tip of the leaf; this may often be observed in Zantedeschia.

About 900 species in 100 genera. Home, the Tropics, especially S. America, India, and the Indian Islands, preferably in shady, damp forests growing as epiphytes upon trees, and on the banks of streams. Outside the Tropics few are found. Acorus calamus was introduced into Europe from Asia about 300 years ago; it, however, never sets any fruit, as the pollen is unfertile. In England Arum maculatum is a very common plant; this and A. italicum are the only native species. Colocasia antiquorum comes from Polynesia and the Indian Islands, and also Alocasia macrorrhiza. Fossils in Cretaceous and Tertiary.

Uses. Many species have pungent, and even poisonous properties (e.g. Dieffenbachia, Lagenandra, Arum), which are easily removed by boiling or roasting; the rhizomes of many species of Caladium, Colocasia (C. antiquorum, esculenta, etc.), are very rich in starch, and in the Tropics form an important source of food. An uncommon occurrence in the order is the highly aromatic rhizome of Acorus calamus; this contains calamus-oil and acorin which are used in perfumery. Many are ornamental plants, e.g. Zantedeschia æthiopica (South Africa), generally known as “Calla,” and Monstera deliciosa; many other species are grown in greenhouses.

Order 6. Lemnaceæ (Duck-weeds). These are the most reduced form of the Spadicifloræ. They are very small, free-swimming water-plants. The vegetative system resembles a small, leaf-like body (Fig. 303 f-f), from which roots hang downwards; this branches by producing a new, similar leaf-like body, which springs from a pocket-like hollow (indicated by a dotted line in the figure) on each side of the older one, at its base (or only on one side). The branching is thus dichasial or helicoid (Fig. 303 A, where f, f′, f″, f″′ indicate shoots of 1st, 2nd, 3rd, 4th generations respectively). The leaf-like bodies are, according to Hegelmaier, leaf-like stems, and thus Lemna has no other leaves than the spathe and the sporophylls; according to the investigations of Engler they are stems whose upper portion (above the “pocket”) is a leaf, which is not sharply separated from the underlying stem-portion. The inflorescence is a very much reduced Araceous-spadix, consisting in Lemna of 1 or 2 stamens of unequal length (1-stamened ♂-flowers), 1 unilocular carpel (♀-flower), and 1 thin spathe (B). [The same is found in Spirodela polyrrhiza, etc., whose daughter-shoots begin in addition with 1 basal-leaf. Wolffia arrhiza, etc., have no roots, no spathe, and only 1 ♂-flower in the inflorescence (Engler).]—On the germination of the seed a portion of the testa is thrown off as a lid, so that an exit is opened for the radicle.—19 species. In stagnant fresh water, both Temp. and Tropical.—In Europe the species are Lemna minor, trisulca, gibba; Spirodela polyrrhiza, and Wolffia arrhiza, the smallest Flowering-plant.

Family 3. Spadicifloræ.