54 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



point. Spikelet 15 mm.; first glume 4.3-4.5 mm.; subulate, hispid 

 on the keel; second 7.3 mm., lanceolate, scabrous, the hispid keel 



much thickened below, extended into 

 a short awn between the teeth of the 

 bidentate apex. Perfect floret: floral 

 glume 6.5 mm., lanceolate^ bearing 3 

 scabrous awns with minute intermedi- 

 ate teeth, middle awn i mm., lateral 

 awns 1.5 mm.; palea 5.5 mm., biden- 

 tate, nerves scabrous; flower some- 

 times pistillate only. Neuter floret: 

 floral glume 12-13 rnm. including the 

 erect, unequal, scabrous awns, with 

 long scabrous intermediate and lat- 

 eral teeth; palea none in specimens 

 examined. Grain not seen. "Cary- 

 opsis linearis, cylindraceous, glabra. " 

 (H. B. K. nov. Gen. et Sp. 1:175, plate 

 55, rig. 7.) 

 -Nohcacab, Nov. 24, 1865, Schott 741. 



Hab. 



Bouteloua Triaeua (Spreng), Scribn. Proc. Phila. Acad. Sci. 1891, 



307- 



Tricena racemosa H. B. K. not Bouteloua racemosa Lag. 



Atheropogon Tricena Spreng. 



Inflorescence short exserted or included at the base, axis 410 

 cm. long, smooth, internodes 1-2 mm. Spikes subsessile, reflexed 

 or spreading, of a solitary spikelet, the rachis continued beyond the 

 spikelet in a scabrous awn-like point longer than the first glume. 

 Spikelet 8-12 mm. long; first glume 2-2.3 mm. linear-oblong, 

 minutely scabrous, obtuse; second glume 4-4.3 mm., lanceolate, 

 acute, sparsely pubescent, scabrous on 

 the keel. Perfect floret: floral glume 6 

 mm., lanceolate, long acuminate, 

 3-nerved, scabrous on the keel; palea 

 nearly equal in length, narrowly lanceo- 

 late, acuminate, nerves scabrous and ex- 

 tended in two slender teeth. The upper 

 floret reduced to 3 slender, equal, erect 

 or diverging scabrous awns, 9-10 mm. 

 long. Grain stramineous, narrowly 

 lanceolate, .4x3 mm. ; in section subor- 

 bicular. 



Hab. Nohcacab, Nov. 24, 1865, 

 Schott 740; top of pyramid of El Cas- 

 tillo, Chichen Itza, Jan. 19, 1895, Mills- 

 paugh, Armour Exped. 135 ; " Old fences 

 and low shrubbery upon which it de- 

 pends for support, 2 feet high, uncommon," Izamal, Aug. Gaumer 

 JO26, Chichankanab 1454, San Anselmo 2142; Tekanto, Feb 25, 

 1890, Stone 210 (in Herb. Phila. Acad. Sci.). 



O 



