Biish — North American Species of Triodia. 65 



Tricuspis Beauv. Agrost. 77, 1812, not Tricuspis Pers. 1807, a genus in 



Tiliaceae. 

 Uralepia Nutt. Gen. 1 : 61. 1818. 

 Windsoria Nutt. Gen. 1 : 70. 1818. — Trans. Am. Phil. Soc. II. 5 : 147. 



1837. 



KEY TO THE SPECIES. 



Spikelets subcompressed, oblong, in a rather dense spikelike panicle. 

 Panicle elongated, spikelets about 5 mm. long. 



Lower scales much longer than the lower flowers. 1. T. strieta. 



Lower scales about as long as the lower flowers. 2. T. albescens. 

 Panicle short, oblong, spikelets about 10 mm. long. 3. T. congesta. 

 Spikelets compressed, crowded in short subcapitate panicles on the simple 

 nearly naked culms, bleaching white at maturity. 

 Flowering scale entire or merely mucronate. 4. T.pilosa. 



Flowering scale deeply cleft at apex ; awns from sinus exceeding the 

 lobes. 

 Flowering scale lance-ovate; lobes subacute. 5. T. grandijlora. 



Flowering scale linear-oblong; lobes obtuse. 6. T. Nealleyi. 



Spikelets compressed, panicle verticillate, short, leafy. 



Flowering scales 4-6 mm. long. 7. T. pulcfiella. 



Flowering scales 2-3 mm. long. 8. T. pulchella parvijlora. 



Spikelets compressed, panicle open, branches spreading. 



Flowering scales entire or emarginate, sometimes mucronate. 



Spikelets 6-12 mm. long; lower scales about one-half as long as 



the adjacent flowering scales. 9. T. Texana. 



Spikelets 5-7 mm. long; lower scales nearly equaling or slightly 



exceeding the adjacent flowering scales. 



Plant mostly smooth, 10. T. eragroatoides. 



Plant scabrous throughout. 11. T. eragroatoides scabra. 



Flowering scales somewhat 3-toothed, the nerves all slightly excurrent. 



Panicle narrow, pedicels stout. 12. T. Langloiaii. 



Panicle open, pedicels slender. 



Sheaths pilose. 13. T. Drummondii, 



Sheaths smooth. 



Spikelets broad, 14. T. Elliottii. 



Spikelets narrow. 



Plant pale, panicle branches spreading with tufts of white 

 hairs in axils of the panicle. 16. T. Chapmani. 



Plant purplish, panicle branches upright. 16, T. seslerioides . 

 Spikelets terete, panicle narrowly linear. 



Lower scales both l-nerved, 17. T. mutica. 



Second lower scale 3-5 nerved, 18, T. elongata. 



1. Triodia stkicta (Nutt.) Benth. ex Vasey, Gr. U. S. 

 35. 1883. 



Windsoria strieta Nutt. Gen. 70. 1818. 



Tricuspis strieta (Nutt.) Munro, A. Gray, Proc. Phila. Acad. Nat. 



Sci, 1862 : 336. 1863. 

 Tricuspis strieta Nutt. fide Heller, Cat. PL N. A. 28, 1900, 



