120 



GRAMINEAE (GRASS FAMILY) 



1. Z. palustris L. (INDIAN RICE, WATER OATS.) Annual; culms 2-3 m. 

 high ; leaves flat, 5-10 dm. long, 1.5-4c m. wide. (Z. aquatica of auth. not L.) 

 Swampy borders of streams and in shallow water; common, 

 especially northwestw. July, Aug. (Asia.) FIG. 73. 



2. Z. aquatica L. Culms about 1 m. high ; leaves nar- 

 rower (less than 1 cm. wide) ; pistillate portion of panicle 

 more appressed. Me. to Minn., and northw. 



17. ZIZANI6PSIS Doll & Asch. 



Spikelets unisexual, the pistillate above, the staminate below 

 on each branch of the panicle, much alike in appearance, 

 laterally compressed ; glumes subequal, membranaceous, the 

 first glume of the pistillate spikelet with a short terminal awn, 

 the lemma acute, palea none ; glumes and lemma of staminate 

 73. Z. aquatica x l. spikelet acute, nerveless, palea none ; stamens 6 ; grain ovoid, 

 cf spikelet. with a chartaceous easily separable pericarp, loosely inclosed 



$ spikelet. in the glumes. A tall aquatic grass with long leaves and 



Pistil with scales, long narrow terminal panicles. (Name from Zizania and 



tyis, appearance, from likeness to the preceding genus.) 

 1. Z. miliacea (Michx.) Doll & Asch. Perennial by a creeping rootstock ; 

 culms 1-4 m. high, geniculate at the lower nodes; leaves flat, 3-10 dm. long, 

 1-3 cm. wide. (Zizania Michx.) Swamps, Va., O., and south w. May. 



18. LEERSIA Sw. CUT-GRASS. WHITE GRASS 



Spikelets 1-flowered, flattened laterally, perfect, but those in the open panicles 

 usually sterile, those inclosed in the sheaths cleistogamous and fruitful ; glumes 

 none, lemma boat-shaped, somewhat indurated, awnless, 

 clasping the palea by a pair of strong marginal nerves ; palea 

 of like texture, much narrower, 1 -nerved ; stamens 1-6. 

 Perennials of moist ground, with rough leaves and short 

 racemes of imbricated spikelets arranged in open panicles. 

 (Named after Johann Daniel Leers, a German botanist of 

 the 18th century.) HOMALOCENCHRUS Mieg. 



* Spikelets narrowly oblong, rather loosely crowded. 



1. L. virginica Willcl. (WHITE GRASS.) Culms weak, 

 branched, ascending, with clustered scaly rootstocks ; panicle 



simple, the slender branches stiffly spread- 74. L. virginica. 

 ing; spikelets 2.5-3 mm. long, closely ap- A bit of inflorescence 

 pressed ; lemma hispid on the keel ; stamens * 3. 

 2. Wet woods, Me. to Ont., and south w. Spikelet x 5. 

 Aug. FIG. 74. 



2. L. oryzoides (L.) Sw. (RICE CUT-GRASS.) Culms rather 

 stout, branched, ascending from a decumbent base with slender 

 creeping rootstocks; leaves very rough; panicle diffusely 

 branched, lax ; spikelets 4-5 mm. long ; lemma hispid, strongly 

 bristly ciliate on the keel. Swamps or stream borders, ditches, 

 etc., Nfd. to Ont., and south w. Aug., Sept. (S. A., Eurasia.) 

 FIG. 75. 



* * Spikelets broadly oval, imbricately covering each other. 



Inflorescence x vi>. ^. *" lenticularis Michx. (CATCH-FLY GRASS.) Culms 

 A bit of same x %! nearly simple, erect or decumbent at base, with scaly root- 

 Open spikelet x 2. stocks ; sheaths and blades sometimes nearly smooth ; panicle 

 nearly simple ; spikelets very flat, 5 mm. long, strongly bristly- 

 ciliate. Low grounds, Va. to Minn., and southw. 



