Part 47

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 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.