WOOTON AND STANDLEY FLORA OF NEW MEXICO. 49 



Spikelets 2 to 6 at each joint of the rachis or if solitary 

 the glumes arranged obliquely to the rachis. 

 Spikelets l-flowered or with a rudimentary second 



flower 72. Hordeum (p. 106). 



Spikelets 2 to many-flowered. 



Rachis of the spikes jointed, readily breaking 



' into joints ! 73. Sitanion (p. 107). 



Rachis of the spikes continuous, not breaking 



into joints 74. Elymus (p. 108). 



1. THIPSACUM L. 



Tall stout perennial with creeping rootstocks, broad flat leaves, and terminal digitate 

 inflorescence, the spikes separating into joints at maturity; spikelets unisexual, the 

 staniinate in pairs at the joints of the rachis above, the pistillate solitary, embedded 

 in each joint of the racliis below in the same inflorescence; glumes of the staminate 

 spikelet subcoriaceous, those of the pistillate sinkelet finally cartilaginous, the lemmas 

 and paleas hyaline. 



1. Tripsacum lane eola turn Rupr.; Foum. Mex. PL 2: 68. 1886. 

 Type locality: Aguas Calientes, Mexico. 

 Range: Southwestern New Mexico to southern Mexico. 

 New Mexico: Guadalupe Canyon (E. C. Merton 2035). 



2. TRACHYPOGON Nees. 



Rather tall perennials with narrow leaves and usually solitary, long-exserted 

 racemes; spikelets l-flowered, in pairs at the nodes of the imperfectly jointed rachis, 

 one nearly sessile, awnless, sterile, the other pedicellate, fertile, long-awned; glumes 

 rigid, the outer large and inclosing the other; lemmas produced into long twisted 

 geniculate awns. 



1, Trachypogon montufari (H. B. K.) Nees, Agrost. Bras. 342. 1829. 



Androjwgon montvfari H. B. K. Nov. Gen. & Sp. 1: 184. 1816. 



Type locality: "In aridis, apricis regni Quitensis prope Conocoto, Pintae et Vil- 

 1am Chilloensem Montufari." 



Range : New Mexico and Arizona to Mexico and South America. 



New Mexico: Near Wliite Water {Mearns 353). Dry hills. 



3. ELYONTJRTJS Humb. & Bonpl. 



Low or tall annuals or perennials with rather rigid leaves and solitary terminal 

 racemes; spikelets l-flowered, awnless; first glume rigid or subcoriaceous, 2-tootlied 

 at the apex, the margins inflexed, more or less ciliate, with balsam-bearing lines 

 between the lateral keels, the second a little shorter than the first, acute; lemma 

 delicate and hyaline ; palea minute or none; stamens 3; styles distinct. 



1. Elyonurus barbiculmis Hack, in DC. Monogr. Phan. 6: 339. 1889. 

 Type locality: Western Texas. 



Range : Southern New Mexico and Arizona to western Texas and adjacent Mexico. 

 New Mexico: Dog Spring (i/eams 2376). Dry hills. 



4, SCHIZACHYRITJM Nees. Sage grass. 



Tall perennials, tufted or from rootstocks, with flat or involute leaves, and spikelike 

 solitary racemes terminating the stem or its branches; spikelets in parrs at each node 

 of the jointed and often hairy rachis, one sessile and fertile, the other pedicellate and 

 sterile; glumes indm-ated, sometimes pubescent; lemma entire or 2-toothed at the 

 apex, bearing a straight, contorted, or spiral a^mi; palea small, hyaline; stamens 1 to 

 3; styles distinct. 



52576°— 15 4 



