418 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



spikelets 3 to 5, consisting of a lower perfect floret and an upper rudiment; glumes 

 narrow, hispid, keeled, the first about 3 mm., and the second about 5 mm. long, 

 smooth, with 3 short, hispid awns, the central awn not over 0.5 mm. longer than 

 the lateral; palet the same length as its lemma, with two short awns from the two 

 nerves; rudiment usually consisting of a single 3-awned lemma, the central awn 

 being by far the most important, often 9 to 10 mm. long, the lateral awns only 2 mm. 

 long, infolded; caryopsis flattened, 1.75 mm. long, 0.5 mm. wide, the small scu- 

 tellum covering only about one-third of the ventral surface. (Figure 61.) 



The description is drawn from Snodgrass & Heller 393, James Island, Galapagos, 

 April, 1899. This appears to be a good, average specimen, although it does not cover 

 all of the many variations. The spikelet described is from the middle of the spike. 

 In the lower spikelet the rudiment is usually much smaller than described, at times 

 even reduced to a single awn half as long as the perfect floret. It is exceedingly 

 variable and is more closely related to B. curtipendula than to any other species. 

 The Hopkins Galapagos Expedition furnished a fine series of specimens, the best 



representatives of which are in the Gray Herba- 

 rium. Some of them might be considered an- 

 nual, but no. 507 is clearly perennial. In general 

 aspect this certainly looks like B. curtipendula. 



35. Bouteloua uniflora Vasey. 



Bouteloua uniflora Vasey, Bot. Gaz. 16:26. 

 1891. The type is Nealley 222, Crockett County, 

 Texas, 1890, in the National Herbarium. See 

 also U. S. Dept. Agr. Div. Agrost. Bull. 7 : 212. 

 /. 194. 1897. 



DESCRIPTION. 



A tall, smooth, tufted, erect perennial, with 

 the habit and general appearance of B. curtipen- 

 dula; culms simple or branched at the very 

 base, 35 to 50 cm. high; sheaths striate, smooth 

 or minutely rough-hispid under a lens, the ligule 

 reduced to a ring of short, flexuous, white hairs; blades variable, from 2 to 10 cm. 

 long, the longest above, striate, minutely hispid, especially on the upper surface 

 and on the involute edges, the latter being also sparsely papillose-ciliate; panicle 

 racemose, exactly like that of B. curtipendula excepting for the smaller spikes; 

 spikes' 25 to 35, 8 to 9 mm. long, consisting of a 1-flowered spikelet and a hispid, 

 closely appressed prolongation of the rachis, about 4 mm. long; second glume 7 to 8 

 mm. long, 1 mm. wide, acuminate, the first about 3 mm. long, 0.8 mm. wide, with 

 a more rounded apex; lemma smooth, 3-nerved, very short-awned or awnless, about 

 6 mm. long, with a narrow, 2-toothed, smooth palet, about 5 mm. long; rudiment 

 consisting of a single, simple, hispid awn about 4 mm. long; caryopsis not known. 

 (Figure 62.) 



The specimen is immature, and it is barely possible that it may turn out to be an 

 aberrant form of B. curtipendula. Bigelow, "Rio San Pedro, Texas," November 5, 

 1850, in the herbarium of S. M. Tracy, from the Thurber Herbarium, is the same as 

 the type in every floral detail, but the spikes are more numerous. No collections 

 other than these two have been seen. 



Fig. 62.— Bouteloua uniflora. a, Spike, of 

 single spikelet with prolongation of 

 rachis; 6, c, lemma and palet; d, rudi- 

 ment, o, Scale 5; b-d, scale 13. From 

 type specimen. 



