682 



GRAPTOPHYLLUM 



GRASS 



elliptic, acuminate, irregularly marked with yellow along 

 the midrib: fls. crimson, in axillary whorls; corolla pu- 

 bescent. Habitat? B.R. 15:1227. Lowe 45. (B.M. 1870 

 shows a variety with reddish brown coloring). 



GRASS (Graminece). Annual or perennial herbs 

 (some bamboos woody), mostly tufted or decumbent, 

 rarely climbing, often creeping and rooting at the base. 

 True roots fibrous. Stems (culms) simple or branching, 

 usually hollow (wheat), sometimes solid (maize) between 

 the nodes. Leaves springing from the nodes, alternate, 

 in two vertical rows on the stem; the sheaths closed 



983. Spike of a Grass (rye), containing many flowers. 



when young, but usually split down one side in matur- 

 ing; ligule a thin tongue-like growth at the apex of the 

 sheath ; blade entire, parallel-veined, commonly long 

 and narrow ; a 2-keeled membranous prophyllum (or 

 leaf) always standing between each branch and the 

 main axis. Spikelets in panicles, racemes or spikes, 

 usually consisting of 2 (rarely 0, 1, or more than 2) 

 chaffy empty glumes- at the base of a short axis (ra- 

 chilla), which supports one or more floral glumes, in the 

 axil of each of which is commonly 1 flower. Flowers 



perfect or imperfect, destitute of true calyx or corolla. 

 Between each floral glume and flower are usually 2 

 (rarely 3) minute hyaline scales (lodicules). Stamens 

 3 (rarely 1, 2 or more than 3) ; pistil 1: ovary 1-celled, 

 1-ovuled ; styles 2 (rarely 1 or 3), usually ' plumose: 

 fruit (grain or caryopsis) seed-like, often enclosed by 

 the palet and its floral glume. Seed erect, closely cov- 

 ered by the thin pericarp; embryo small, on one s'ide of 

 the base of the endosperm. Figs. 981-984 show the 

 structure of various Grass florets. 



Perennial Grasses, such as those commonly grown for 

 meadow, pasture or lawn, produce large numbers of 

 sterile shoots that bear leaves from very short stems, 

 but no flowers. There are many widely different plants, 

 which in popular language have the name "grass" at- 

 tached to them, such as knot-grass, rib-grass, cotton- 

 grass, sea-grass, eel-grass, sedge-grass, scorpion-grass, 

 but these do not belong to the family here under consid- 

 eration. Neither are the clovers and their allies, or the 

 sedges and rushes, to be called Grasses. No other 

 plants are truly entitled to this name, excepting those 

 answering to the description above given. 



The plants most likely to be mistaken for Grasses are 

 the sedges (Cyperaceae), of which there are large num- 

 bers in great variety frequently found on wet land. The 

 best popular way to distinguish Grasses from sedges 

 is this: the leaves of sedges are arranged on 3 sides 

 or angles of the stem, while on Grasses they are found 

 on 2 sides, alternate and 2-ranked. In making use of 

 this test, care must be taken to select well grown, erect 

 stems. Most sedges have solid stems and most Grasses 

 have hollow stems. .To learn to distinguish plants of the 

 Grass family is easy, but to discriminate between spe- 

 cies is difficult. 



Among the species most commonly known are timo- 

 thy, red top, June-grass, orchard-grass, meadow fox- 

 tail, the fescues, oat-grass, sweet-vernal, quack-grass, 

 Bermuda-grass, sugar cane, chess, and the cereals, such 

 as wheat, barley, rye, oats, rice, sorghum, Indian 

 corn. In number of species the Grass family occupies 

 the fifth place with 3,500, while the compositae, legumes, 

 orchids and madderworts are larger. In number of inc" 

 viduals, the Grasses excel any other family. Seed plant 

 are arranged in 200 to 220 families, and of all these tl 

 true Grasses are of greatest importance to man ; in fs 

 they are of more value as food for man and domest 

 animals than all other kinds of vegetation combine 

 None of these families is more widely distributed ovt 

 the earth's surface, or is found in greater extremes 

 climate or diversity of soil. 



The species are very numerous in tropical regions 

 where the plants are usually scattered, while in a mois 

 temperate climate, though the species are less numt 

 ous, the number of plants is enormous, often clothii 

 vast areas. Where soil is thin or moisture insufficiei 

 the Grasses grow in bunches more or less isolate 

 Plants of one section of the family Panicacese predomi 

 nate in the tropics and warm temperate regions, whil 

 plants of the other section, Poaceae, predominate in tem- 

 perate and cold regions. 



Overstocking dry grazing districts checks the better 

 Grasses, destroying many of them, and encourages tl 

 bitter weeds which multiply and occupy the land. 



A Grass extends its domain by running rootstocks, 

 liberating seeds enclosed in the glumes, which ai 

 caught by the breeze, by some passing animal, or tl 

 nearest stream ; the twisting and untwisting of a\ 

 bury some of them in cracks, crevices or soft ear 

 In case a growing stem is thrown doAvn for any reas 

 several of the lower nodes promptly elongate on ti 

 lower side and thus bring the top into an erect positioi 

 Each sheath supports and holds erect the tender 

 portion of the internode, where it is soft and weak; 

 also protects the young branches or panicles. Thrif 

 blades of Grasses suitable for pasture and lawn elong 

 from the lower end, so that when the tips are cut 

 the leaves do not cease to elongate, but renew th( 

 length. When exposed to sun or dry air, the blades d< 

 velop a thicker epidermis, and, by shrinking of soi 

 of the delicate bulliform cells of the upper epidermis 

 they diminish their surface as they roll their edges ii 

 ward or bring them together, like closing an oneu bool 

 When the plant is in flower the minute and delica " 



