FEB. 1903. PLANTS YUCATAN^E MILLSPAUGH.I& 



53 



Bouteloua Americana (Sw.) Scribn. Proc. Phila. Acad. Sci. 1891, 



306. 



Aristida Americana Swartz non L. f. 

 Dinebra repens H. B. K. 

 Bouteloua bromoides Lag. 



Inflorescence exserted, axis 5-10 cm. long, subflexuous, minutely 

 scabrous, internodes 10-20 mm. below, 3-5 mm. toward the summit. 

 Spikes subsecund, ascending on short scabrous pedicels, 1.5-2 cm. 



long, of 3-10 spikelets, the sca- 

 brous rachis continued to a naked 

 slender point. Spikelet 10-12 

 mm. long; first and second 

 glumes ovate-lanceolate, hispid- 

 ulous on the keel,, acuminate, 

 first 3.8-5 mm., second 4.3-5.7 

 mm. Perfect floret: floral glume 

 6-7 mm., sometimes with a tuft 

 of hairs at the base, oval-lanceo- 

 late, bidentate, with a scabrous 

 awn i mm. long between the 

 teeth; palea 5.6-7 mm., nerves 

 scabrous, bidentate. Staminate 

 floret: floral glume 9-10 mm. 

 (including the erect, scabrous 

 awns), oval-lanceolate, the mid- 

 dle awn longest and having a slender tooth on each side; palea 4.56.5 

 mm., similar to that of perfect floret, enfolding a staminate flower and a 

 rudimentary pistillate flower or an abortive staminate flower or empty 

 (or rarely a perfect flower, the lower floret being pistillate); the 

 rachilla extended in a slender appressed tip back of the palea. Grain 

 ochraceous .7x4.3 mm. Only immature seeds found. 



A species "variable in size, habit and number of spikelets, but 

 the floral characters uniform within narrow limits." (S. Watson in 

 Am. Acad. Sci., 1883, p. 178.) The floral characters in specimens 

 examined vary mostly in size of glumes and in having the upper floret 

 either staminate or neuter or (Schott 659) in having a pistillate flower 

 below and a perfect flower above. Apparently the species rarely 

 perfects seed in any known habitat. 



Hab. Merida, Sept., Oct. and Nov., 1865, and at ruins of Uzmal, 

 Sept. 16, 1865, Schott 656, 742, 659; " brushlands near Izamal, 

 uncommon, 3 feet high," Oct., Gaunter fOj6, San Anselmo, 1262. 

 Depauperate specimens from Tekanto, Feb. 28, 1890, Stone 189 (in 

 Herb. Phila. Acad. Sci.). 



Bouteloua disticha (H. B. K.) Benth. Jour. Linn. Soc. 19:105. 



Polyodon distich urn H. B. K. 



Inflorescence included at base, axis 16 cm. long, scabrous, inter- 

 nodes 10-12 mm. below, 3-4 mm. toward the summit. Spikes sub- 

 secund, ascending or spreading on short scabrous pedicels, 1.5-1.7 

 cm. long, of 3-4 spikelets, the hispid rachis continued to a naked bifid 



