76 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



having acuminate lemmas. These four species and T. mwtica (Torr.) 

 Scribn. agree in having woolly lemmas, the lower part of the three 

 nerves being long-villous, and in having paleas villous on the wings. 

 Tmodia rrmtica has a somewhat elongate panicle and differs in having 

 very obtuse, broad, sometimes minutely notched, awnless lemmas, the 

 lateral nerves disappearing before reaching the margin. The afore- 

 mentioned species might be set off under Erioneuron, but they would 

 not form a coherent group. 



Triodia flava (L.) Hitchc. (Poa flava L.) (fig. 35) has an open, 

 elegantly drooping panicle of purple spikelets, the nerves of the 

 lemmas pubescent below, extending into 3 mucros. This is common 

 in autumn through the Eastern States in meadows and open wood- 

 land and is sometimes called purple-top. It exudes a sticky sub- 

 stance on the culm below the panicle and on the main branches of 

 the inflorescence, to which dirt adheres. One species, T. drum- 

 mondii Scribn. and Kearney, produces rhizomes. 



Three species (besides T. mutica mentioned above) have a spike- 

 like panicle. These are T. aTbescens Vasey, with glabrous lemmas; 

 T. elongata (Buckl.) Scribn., with glumes nearly as long as the 

 spikelet; and T. stricta (Nutt.) Yasey, with shorter glumes but mu- 

 cronate lemmas. The other species have more or less open panicles. 



In general the species of Triodia are of little importance agricul- 

 turally. Triodia pulchella is often abundant on the ranges, but is 

 not relished by stock, the little dry plants being seldom eaten. 



27. TRIPLASIS Beauv. 



Spikelets few-flowered, the florets remote, the rachilla slender, 

 terete, disarticulating above the glumes and between the florets; 

 glumes nearly equal, smooth, 1-nerved, acute; lemmas narrow, 

 3-nerved, 2-lobed, the nerves parallel, pubescent or villous, the lateral 

 pair near the margin, the midnerve excurrent as an awn, as long as 

 or longer than the lobes ; palea shorter than the lemma, 2-keeled, the 

 keels densely long-ciliate on the upper half. 



Slender tufted annuals or perennials, with short blades, short, open, 

 few-flowered purple panicles terminating the culms, and cleistoga- 

 mous narrow panicles in the axils of the leaves. Species three ; south- 

 eastern United States. 



Type species : Triplasis americana Beauv. 



Triplasis Beauv., Ess. Agrost. 81, pi. 16, f. 10. 1812. The single species, 

 T. americana, is figured. 



Uralepis Nutt., Gen. PL 62. 1818. Nuttall describes two species, U. purpurea, 

 based on Aira purpurea Walt. (Triplasis purjmrea (Walt.) Chapm.) and U. 

 aristulata, which is the same species. The first is selected as the type. The 

 name is spelled Uralepsis, but this is a typographical error. Nuttall states 

 that it is based on the Greek words oiira and lepis. 



Diplocea Raf., Amer. Journ. Sci. 1 : 252. 1819. One species described, D. 6or- 

 bata, which is the same as Triplasis purpurea. 



Merisachue Steud., Syn. PI. Glum. 1: 117. 1854. Contains one species, 

 M. drummondii Steud., Drummond 330, from Texas (Triplasis purpurea). 



