FLORA OF THE DISTRICT OF COLUMBIA. 71 



1. TRIPS ACUM L. 



1. Tripsacum dactyloides L. Gam a grass. 



Low moist or wet ground; abundant in a few localitiiis in the flood plains of the 

 Potomac and occasional elsewhere. Aug. Southeastern U. S., north to N. Eng. 



Growing in large clumps and forming hard mats of thick horizontal rootstocks Ijdng 

 on or near the surface. This and Zizania palushis are the only native monoecious 

 grasses of this region. 



2. MISCANTHUS Anderss. 



1. Miscanthus sinensis Anderss. Eulalia. 



Escaped from cultivation and established on wooded hillsides in the vicinity of 

 Mount Pleasant, Cleveland Park, Chevy Chase, and Forest Glen. Aug.-Sept. Native 

 of Asia. 



Cultivated for ornament; growing in large tufts, with numerous narrow blades 

 60-120 cm. long, and slender upright flower stalks 1-2 meters high, bearing fan- 

 shaped clusters of woolly racemes 15-30 cm. long. The blades are often variegated 

 with bands or stripes. Known to gardeners as Eulalia japonica. 



3. ERIANTHUS Michx. 



1. Erianthus saccharoides Michx. 



Wet meadows and swales; occasional in the vicinity of Brightwood and Kenilworth. 

 Aug.-Oct. Southern states, north to N. J. (E. alopecuroides of Ward's Flora.) 



A striking species, with culms as much as 2 meters tall, bearing a dense feathery 

 plume 10-20 cm. long. Oui form with somewhat more compact panicles has been 

 described as E. coinpactus Nash. 



Arthraxon ciliaris cryptatherus Hack, has been found on the Chevy Chase golf 

 course. Culms creeping; blades ovate-lanceolate, cordate, ciliate at base; racemes 

 slender, several in a fascicle. Introduced from Japan. 



4. ANDROPOGON L. 



Racemes borne singly on the few to many branches. (Subgenus Schizachyriian). 



1. A. scoparius. 



Racemes 2 to several together, digitate or nearly so, the common peduncle often 



inclosed in a bractlike sheath or spathe, these sometimes in groups forming a 



compound inflorescence. 



Pedicellate spikelet staminate, as large as the sessile spikelet; terminal racemes 2 



to several, exserted on a naked peduncle, the uppermost sheath inconspicuous, 



not inflated, the lateral inflorescences usually less exserted; rachis straight and 



stiff, the hairs inconspicuous and shorter than the spikelets. . .2. A. furcatus. 



Pedicellate spikelet reduced to 1 or 2 empty glumes; racemes in pairs from a broad, 



conspicuous, usually inflated spathe; rachis flexuous, capillary, the hairs 



conspicuous and as long as or longer than the spikelets. 



Uppermost pair of racemes long-peduncled, their spathe inconspicuous, the 



lateral pairs short-peduncled from large, inflated, aggregate, sometimes 



blade-bearing sheaths 3. A. elliottii. 



Uppermost pair of racemes on peduncles not longer than those of the lateral ones, 

 all the spathes about equally inflated. 

 Spathes scattered or in small clusters along the slender culm; spikelets about 



3 mm. long 4. A. virginicus. 



Spathes aggregate in a dense, flabellate or oblong, compound inflorescence; 

 spikelets about 4 mm. long 5. A. glomeratus. 



