384 



CONTRIBUTIONS FROM THE NATIONAL, HERBARIUM. 



the ligule a ciliate, hairy ring; spikes 4 to 6 or 7, 1.5 cm. long; spikeleta 25 to 40, 

 about 3 mm. long over all, consisting of a floret and a rudiment; glumes hispid-keeled, 

 short-awned, the awn subtended on either side by short, lanceolate-pointed teeth of 

 the lamina of the glume, the first 2 mm., the second 3 mm. long; lemma 3.5 to 4 mm. 

 long, densely hairy, having 3 equal, hispid awns, with 2 comparatively large, laminar 

 teeth between them and a smaller one at either side; palet 3 mm. long, 2-awned and 

 4-toothed, bearing a few scattered hairs on the outside of the nerves; caryopsis oval, 

 about 1 mm. long or less, rounded or slightly flattened on the back, the ventral sur- 

 face nearly covered by the scutellum. (Plate 73, B, facing p. 382. Figures 38, 39.) 

 The species is variable, sometimes growing a foot high and sometimes only an inch 

 (see plate), its size depending upon the character of the soil and the amount of rain- 

 fall. In our Southwestern 

 States and in Mexico east 

 of the Pacific coast region 

 it has two quite distinct 

 forms, one with short awns, 

 the other with long awns, 

 making the spike much 

 wider in the latter case. 

 The long-awned form very 

 closely approaches B. are- 

 nosa of the Pacific coast of 

 Sonora, but that species 

 has still heavier spikes. 

 Further study, however, 

 may require the inclusion 

 of that species here. I do 

 not feel warranted at pres- 

 ent in making a change 

 in the nomenclature, for 

 my field experience haa 

 not brought me in contact 

 with the arenosa form. 



Pringle's 13626, Schaffner 

 183 and 187, Rothrock 352, 

 Wooton 398, Bourgeau 667, 

 Metcalfe 701, are all typi- 

 cal of this species, although 

 showing some variation in 

 the length of the awns and 

 in the size of the plants, 

 and consequently a decided difference in general aspect. Two specimens, from 

 Lower California, Brandegee, San Jose del Cabo, 1890, and Purpus, Cape Region, are 

 doubtfully referred here. 



HERBARIUM SPECIMENS. 



Fig. 39.— Boutcloua barbata. a, Spikelet; 6, c, lemma and palet of 

 first floret; d, e, rudimentary second and third florets; /, two views 

 and cross section of caryopsis. a, Scale 7.5; b-f, scale 15. From Griffiths 

 6095. 



Arizona: Tourney in Seymour's Grasses 85, Tucson. Hitchcock 3668, Patagonia; 

 3489, Tucson. Purpus 8293, Beaver Creek. Blumer 1706, Paradise. Mearns 

 1121, San Pedro River near Mexican boundary; 2765, Quitovaquito. Griffiths 

 1897, Wilcox; 2009, Benson; 1646, Sulphur Spring Valley; 1524, Tucson; 3400, 

 Santa Rita Forest Reserve; 3360, Tucson. KnowUon 194, San Francisco Moun- 

 tains; Lemmon 4644; Davidson 41a, Clifton; Griffiths & Thornbcr 254, Santa Rita 

 Mountains. Jones 6063, Buckskin Mountains. Rothrock 352, Cottonwood. 

 MacDougal 571, Fort Verde. Leibcrg 5922, Grand Canyon at Bright Angel Trail. 



