120 



GRAMINEAE (gRASS FAMILY) 



1 Z paliistris L. (Ixdian Rice, Water Oats.) Annual ; culms 2-3 m. 

 high • leaves flat, 5-10 dm. lonij, 1.6-4c m. wide. (Z. aqnatica of aulh. uot L.) - 

 ' Swampy borders of streams and in shallow water; common, 



especially northwestw. July, Auir. (Asia.) Fig. 73. 



'> Z aqudtica 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 



w^i^ on each branch of the panicle, much alike in appearance, 



\J^ j# laterally compressed; glumes subequal, membranaceous, the 



11 ^^^ hrst glume of the pistillate spikelet with a short terminal awn, 



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



spikelet acute, nerveless, palea none ; stamens G ; grain ovoid, 



with a chartaceous easily separable pericarp, loosely inclosed 



in the glumes. — A tall aquatic grass with long^ leaves and 



long narrow terminal panicles. (Name from Zizania and 



6^1/ S, appearance, from likeness to the preceding genus.) 



1 Z. miliacea (xMichx.) Doll & Asch. Perennial by a creeping_rootstock j 



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. 



73. Z. aquatica x 1 

 J' spikelet. 

 9 spikelet. 

 Pistil with scales. 



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 Joliann Daniel Leers, a German botanist of 

 the 18th century.) Homalocenchrus Mieg. 



* Spikelets narrowly ohlong, rather loosely crowded. 



1. L. virglnica Willd. (White Grass.) Culms weak, 

 branched, ascending, with clustered scaly rootstocks ; panicle 

 simple, the slender branches stiffly spread- 

 ing ; spikelets 2.5-3 mm. long, closely ap- 

 pressed ; lemma hispid on tlie keel ; stamens 

 2. — Wet woods, Me. to Ont., and southw. 

 Aug. Pig. 74. 



2. L. oryzoides (L.) Sw. (Rice Cut-grass.) Culms rather 

 stout, branched, ascending from a decumbent base with slender 

 creepinq 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 southw. Aug., Sept. (S. A., Eurasia.) 

 Fig. 75. 



* * Spikelets broadly oval, imbricately covering each other. 



74. L. virginica. 

 A bit of inflorescence 



x3. 

 Spikelet x 5. 



75. L. oryzoides. 

 Inflorescence x ^/^. 

 A bit of same x %, 

 Open spikelet x 2. 



ciliate. 



3. L. lenticularis Michx. (Catch-fly Grass.) Culms 

 nearly simple, erect or decumbent at base, with scaly root- 

 stocks ; sheaths and blades sometimes nearly smooth ; panicle 

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

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



