8 



BOXJTELOUA MICRANTHA Scribn. Oc Merrill sp. nov. 



A very s^leiider, erect, cwspitose, glabrous perennial 7-9 dm. high, with sparingly- 

 branched culms, which are geniculate below, 6-10 very slender, erect or 

 ascending, densely flowered spikes 2-2.5 em. long, and very small spikelets. 

 Sheaths shorter than the internodes, glabrous; ligule a ciliate fringe about 2 

 mm. long; leaf-blades 5-8 cm. long, about 3 mm. wide, with few long papil- 

 late hairs on the margins and often on the upper surface. Panicle 1.5-2 dm. 

 long, the spikes about equaling or the upper ones exceeding the internodes, com- 

 mon rachis smooth. Pedicel of the spikes about 2 mm. long, minutely short- 

 pubescent; the rachis flattened, scabrous on the margins. Spikelets crowded in 

 two rows, secund, purplish, 2-2.5 mm. long; empty glumes unequal, the first 

 hyaline, lacerate at the apex, a1x)ut 1 mm. long, the second firm, purplish, ovate, 

 pubescent, Avith few short, stiff hairs, cleft at the apex, the midnerve prominent, 

 excurrent as a stout awn 0.5 mm. in length; flowering glume about 2 mm. long, 

 pilose with rather long, ascending hairs below and on the margins, smooth above, 

 three-cleft, three-awned, the awns from the cleft less than 1 mm. long, scarcely 

 exceeding the lobes of the glume, the two middle lobes broad, obtuse, the lateral 

 ones very narrow, acute. Palea equaling the glume, 4-toothed, the teeth ciliate. 

 Awns 2, very short. Sterile rudiment on a pedicel about 0.5 mm. long, with a 

 tuft of few short hairs at the apex, consisting of three glumes and three awns 

 which are somewhat longer than those of the flowering glume. 



Type specimen collected at Fort Lowell, Arizona. David Griffiths, September 1900, 

 No. 1556. No. 244 of E. Palmer's ^Mexican collection for 1897 is the same. 



This species has been confused with Bouteloaa polystadnja and B. inicrostachya, but 

 is strikingly different from those species in habit of growth. It is perhaps most 

 closely related to Bouteloua rothrocHi, but is distinguished by its very slender 

 habit, smaller, narrower spikes, much smaller spikelets, and shorter awns. 



Bouteloua oligostachya (Nutt.) Torr. in A. Gray, Man. Bot. ed, 2, 553. 1856. 



{Atlteropogon oligostadtyus 'Suit. Gen. 1 : 78. 1818.) 

 AVilcox, No. 1905; near Pearce, No. 1980; University grounds, Tucson, No. 1552; 



Dragoon Mountains, No. 1863; Sulphur Spring Valley, R. H. Forbes, No. 1640. 



Bouteloua polystachya (Benth.) Torr. Pac. R. R. Rept. 45:366, t. 10. 1847. 



{Cliondrosium jiohi-itadtyumBenth. Bot. Voy. Sulph. 56. 1841.) 

 Wilcox, No. 1897, abundant on sandy ground; Benson, No. 2009; University grounds, 



Tucson, No. 1524; Sulphur Spring Valley, R. H. Forbes, No. 1646; Rincon 



Mountains, No. 1785. 



Bouteloua vestita (S. Wats.) Scribn. Contr. U. S. Nat. Herb. 2 : 531. 1894. {B. 



polystiickya vestita S. Wats. Proc. Am. Acad. 18 : 177. 1883.) 

 Mescal, No. 1819; Pearce, No. 1927. 



Dactyloctenium aegyptium (Linn.) Willd. Enum. 1029. 1809. 

 University grounds, Tucson, No. 1515. 

 liBptocliloa dubia (H. B. K.) Nees, Syllog. Ratisb. 1:4. 1824. {Chloris ditbia 



H. B. K. Nov. Gen. et Sp. PI. 1 : 169. 1815; Diplachne dubia Scribn. Bui. Torr. 



Bot. Club, 10 : 30. 1883.) 

 Cochise, No. 181; near Pearce, No. 1943; University grounds, Tucson, No. 1539, a 



young plant. 

 Leptochloa fascicularis ( Lam. ) A . Gray, Man. Bot. 588. 1848. ( Festuca fascicularis 



Lam. Tabl. Encycl. 1 : 189. 1791; Dipladine fascicularis Beauv. Agrost. 160. 



1812.) 

 Fairbank, No. 1971. 



Leptochloa mucronata (Michx.) Kunth, Rev. Gram. 1 : 91. 1835. {Eleusinemucro- 

 wda Michx. Fl. Bor. Am. 1 : 65. 1803. ) 

 University grounds, Tucson, No. 1513. 



