Locally abundant in alkaline or alkaline-saline areas such as marshes, lakes 

 and irrigation ditches, in Okla. (Alfalfa Co.) and w. half of Tex., N. M. (Guada- 

 lupe, Sandoval, Chaves and Valencia cos.) and Ariz. (Coconino Co.), summer-fall; 

 w. U. S. e. to the Dakotas, Neb., Kan., Okla., Tex., Coah. and Chih. 



11. Chasmanthium Link 



A North American genus of 5 species. 



1. Chasmanthium latifolium (Michx.) Yates. Inland sea oats. Fig. 90. 



Essentially glabrous rhizomatous perennial; rhizomes short, indurated, forming 

 mats; culms rising singly from the mats, 5-13 dm. long, 1.5-3 mm. thick, usually 

 purplish, reclining and geniculate below, above erect, simple and stramineous, 

 terete; sheaths considerably shorter than the internodes and tightly clasping them; 

 blades lanceolate, 1-2 dm. long, 8-16 mm. broad, divergent, acute, striate-veined; 

 panicles very lax, 15-30 cm. long, of 10 to 30 (to 50) large spikelets drooping 

 at the ends of mostly naked capillary branches 3-10 cm. long; spikelets very 

 strongly laterally compressed, 12- to 18-flowered, 25-45 mm. long, 13-16 mm. 

 broad; rachis of spikelet with zone of abscission at the lower part of each node; 

 glumes subequal, 5-7 mm. long, about 1 mm. broad, cymbiform, shorter than 

 the lowest lemma; lemmas broadly lanceolate, 9-13 mm. long, 5-7 mm. broad 

 when unfolded, apically slightly incurved and acutish, grayish to bluish-green, 

 firm, marginally very narrowly hyaline with 3 to 6 nerves on each side, minutely 

 scabrellate, on the keels minutely pectinately scabrous; paleas only two thirds as 

 long as the lemmas and of the same texture, doubly strongly keeled (the keels 

 minutely pectinate), falcate; grain laterally compressed, black, rough, about 3 

 mm. long. Uniola latifoUa Michx. 



Locally abundant in moist loamy soils of creek bottoms, in marshes, in mud 

 and shallow water of streams and ponds, in Okla. (McCurtain, Washington, 

 Murray, Ottawa and Cherokee cos.) and in e. and s.e. Tex., less common w. to 

 n.-cen. Tex., e. Edwards Plateau and n. part of Rio Grande Plains, summer-fall; 

 most of s.e. U.S., n. to Pa., O., 111. and Neb.; also N. L. 



12. Dactylis L. 



A genus of 5 species indigenous to temperate Eurasia. 



1. Dactylis glomerata L. Orchard grass. Fig. 91. 



Densely tufted perennial; culms geniculate, ascending, 6-10 dm. long; ligule 

 a lacerate hyaline scale; sheaths and blades soft, the blades flat and mostly ag- 

 gregated toward the base; panicles long-exserted, mostly narrow, erect, with few 

 mostly ascending branches, each of which bears apically a very dense aggregation 

 (about 1 cm. thick) of secund nearly sessile fascicles of spikelets; spikelets few- 

 flowered, laterally compressed; rachilla abscising at the lower part of each node; 

 glumes and lemmas keeled, the keels hispid; lemmas 5-nerved, about 7 mm. long, 

 narrowly lanceolate, mucronate. 



In stream beds and wet meadows, rare in farm pastures and roadsides in Okla. 

 {Waterfall), the Tex. Plains Country (Lubbock Co.) and N. M. (Taos Co.), 

 spring-summer; widespread in temp, areas, nat. to Euras. 



13. Arundo L. 



About 8 species in the Old World tropics; we have one. 

 1. Arundo Donax L. Giant reed, Georgia cane, carrizo. Fig. 92. 



Canelike grass from thick short rhizomes, forming large clumps; aerial culms 

 2-6 m. long, to 5 cm. thick, erect, rarely branched, perennial or in the northern 

 extremes mostly freezing down annually or every few years; ligule a short scale; 



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