GRASS FAMILY. 



365 



GRAMIN'E^E. (GRASS FAMILY.) 



TRUE GRASSES, with mostly hollow stems (culms) which are cylindrical and jointed, closed 

 at the joints (nodes); leaves alternate, 2-ranked, parallel-nerved, the dilated petiole (sheath) 

 surrounding the culm and split open on the side opposite to the blade, and furnished at 

 the junction with the blade with a more or less manifest scarious appendage (ligule). 

 Flowers perfect, polygamous or monoecious (rarely dioecious), imbricated with 2-ranked 

 glumes or bracts, the outer pair (glumes'), subtending a spikelet of one or several flowers, 

 the inner pair (palece) enclosing each particular flower which is destitute of a proper 

 perianth. Stamens 1-6, usually 3; anthers versatile. Ovary 1 -celled, 1-ovuled, usually 

 with 2 - 3 scales (squamulce) at base. Styles mostly 2 or 2-parted ; stigmas plumose or 

 hairy. Fruit a seed -like grain (caryopsis) ; embryo small at the base and on the outside 

 of copious farinaceous albumen. Annuals or perennials, with fibrous roots, often caespitose. 

 Spikelets paniculate or spiked, upper (inner) palea 2-nerved or 2-keeled. 



This vast Order comprising some 230 genera, and perhaps not less than 3000 species 

 is probably the most generally diffused, and the most important to man, of all the families 

 of plants. The seeds, and herbage, furnish a principal portion of the food of the human 

 race, and of the more valuable domestic animals. A great number of the Grasses, how- 

 ever, are little better than weeds, on a farm, and some of them exceedingly annoying. 

 Those which the American Agriculturist is more immediately interested to know, are here 

 inserted. 



1. THE POA SUB-FAMILY. 



Spikelets 1 - many-flowered ; when more than one-flowered, the lowest developing first, the 

 uppermost if any, imperfect or abortive, the rest perfect, or occasionally monoecious or 

 dioecious except in Nos. 16 and 23, where the lowest florets are staminate. 

 ^ 1. Spikelets 1-flowered, in panicles, the flowers often monoecious. Glumes very small or 

 wanting. Inner palea 3-uerved. Stamens 1-6. 

 Flowers perfect. 



Glumes wanting. Flowers flattened. Palese awnless. 1. LEERSIA. 



Glumes 2, small, cuspidate. Stamens 6. 2. ORYZA. 



Flowers monoecious. 



Fertile flowers awned. 



2. Spikelets 1-flowered, perfect, sometimes with the abortive rudi- 

 ment or pedicel of a second flower above, panicled, the panicle 

 sometimes contracted into a dense spike or head. Stamens not 

 more than three. 



Flowers in a dense cylindrical spike. Glumes equal, strongly 

 flattened, and with the paleae herbaceous. 

 Glumes united at base. Lower palea awned, the upper 



wanting. 

 Glumes distinct at base. Palese 2, the lower truncate and 



awnless. 



Flowers mostly loosely panicled, not strictly spiked, usually 

 small. Glumes equal or unequal, membranaceous. Flower 

 raised on a more or less evident stalk (callus) in the glumes. 

 Flower naked or barely hairy at base. 



Glumes equal or the lower one rather longer, pointless, 



exceeding the very thin, blunt palese. Lower palea 



pointless, commonly awned on the back ; the upper 



sometimes wanting. 



Lower glume mostly smaller. Palese often hairy at base, 



the lower one mucronate or awned at the tip. 

 Flower hairy-tufted at base. 



Lower palea mostly awned on the back, not bristle- 



pointed, shorter than the glumes. 



3. Spikelets (rarely 1-flowered) usually 2 -several-flowered, with 

 one or more of the upper flowers imperfect, disposed in one-sided 

 racemose or digitate spikes. Glumes persistent, the upper one 

 looking outward. Rachis not jointed. Stamens 2 -3. 

 Spikelets with one perfect flower below and one or more neutral 

 ones above. Flower and rudiment awnless. Spikes slender, 

 digitate. 



3. ZIZANIA. 



4. ALOPECURUS. 

 6. PHLEUM. 



7. MUHLENBERGIA. 



8. CALAMAGROSTH. 



9. CYNODON. 



