14 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



(rarely 1 or 3) styles, and usually 

 plumose stigmas; fruit a caryopsis 

 with starchy endosperm and a small 

 embryo at the base on the side oppo- 

 site the hilum. 



Herbs, or rarely woody plants, with 

 hollow or solid stems (culms) closed at 

 the nodes, and 2-ranked usually 

 parallel-veined leaves, these consist- 

 ing of 2 parts, the sheath, enveloping 

 the culm, its margins overlapping or 

 sometimes grown together, and the 

 blade, usually flat; between the 2 on 

 the inside, a membranaceous hyaline 

 or hairy appendage (the ligule). 



The spikelets are almost always ag- 

 gregated in spikes or panicles at the 

 ends of the main culms or branches. 

 The perianth is usually represented 

 by 2 (rarely 3) small hyaline scales 

 (the lodicules) at the base of the 

 flower inside the lemma and palea. 

 The grain or caryopsis (the single seed 

 and the adherent pericarp) may be 

 free, as in wheat, or permanently en- 

 closed in the lemma and palea, as in 

 the oat. Rarely the seed is free from 

 the pericarp, as in species of Sporo- 



bolus and Eleusine. The culms of bam- 

 boos are woody, as are also those of a 

 few genera, such as Olyra and Last- 

 acis, belonging to other tribes. The 

 culms are solid in our species of the 

 tribes Tripsaceae and Andropogoneae 

 and in several other groups. The mar- 

 gins of the sheaths are grown together 

 in some species of Bromus, Danthonia, 

 Festuca, Melica, Glyceria, and other 

 genera. 



The parts of the spikelet may be 

 modified in various ways. The first 

 glume, and more rarely also the sec- 

 ond, may be wanting. The lemmas 

 may contain no flower, or even no 

 palea, or may be reduced or rudi- 

 mentary. Rarely, as in species of 

 Agrostis and Andropogon, the palea is 

 obsolete. 



The division of the family into two 

 subfamilies is somewhat artificial. 

 The tribes Zoysieae, Oryzeae, Zi- 

 zanieae, and especially Phalarideae, 

 do not fall definitely into either of the 

 recognized subfamilies. They are 

 placed as indicated largely for con- 

 venience. 



DESCRIPTIONS OF THE SUBFAMILIES AND KEYS TO THE TRIBES 



SUBFAMILY 1. FESTUCOIDEAE 



Spikelets 1- to many-flowered, the reduced florets, if any, above the perfect 

 florets (except in Phalarideae; sterile lemmas below as well as above in Ctenium, 

 Uniola, and Blepharidachne) ; articulation usually above the glumes ; spikelets 

 usually more or less laterally compressed. 



Key to the tribes of Festucoideae 



Plants woody, the culms perennial. Spikelets several-flowered 1. Bambuseae (p. 27) 



Plants herbaceous, the culms annual (somewhat woody and persistent in Arundo). 



Spikelets with 2 (rarely 1) staminate, neuter, or rudimentary lemmas unlike and below 



the fertile lemma; no sterile or rudimentary floret above 8. Phalarideae (p. 547) 



Spikelets without sterile lemmas below the perfect floret (or these rarely present and like 

 the fertile ones, a dissimilar pair below and a rudimentary floret above in Blephari- 

 dachne). 

 Spikelets unisexual, falling entire, 1-flowered, terete or nearly so. 



10. Zizanieae (p. 561) 

 Spikelets perfect (rarely unisexual but then not as above), usually articulate above the 

 glumes. 

 Spikelets articulate below the glumes, 1-flowered, very flat, the lemma and palea 



about equal, both keeled. Glumes small or wanting 9. Oryzeae (p. 556) 



Spikelets articulate above the glumes (rarely below, but the glumes, at least one, 

 well developed). 

 Spikelets 1-flowered (or the staminate 2-flowered) in groups (short spikes) of 2 to 5 

 (single in Zoysia), the groups racemose along a main axis, falling entire; lemma 



and palea thinner than the glumes 6. Zoysieae (p. 482) 



Spikelets not as above. 



Spikelets sessile on a usually continuous rachis (short-pedicellate in Leptochloa 



