178 PROCEEDINGS OF THE AMERICAN ACADEMY 



HBK., 1. c, t. 51.) In the Caracol Mountains, Coahuila (1354), and 

 at San Luis Potosi (1001 to 1003 Schaftner). Somewhat variable in 

 size, liabit, and number of spikelets, but the floral characters uniform 

 within narrow limits in all the specimens examined from the United 

 States, Mexico, Panama and the West Indies. The second floret is 

 usually stamiuiferous, and the third reduced to a rudimentary awu, 

 often very short. It was found in no case 3-awned, as shown in the 

 figure of Heterostegia juncifolia. Dr. Palmer's specimens represent 

 a large form with large spikes (the same as 2024 Wright and 450 

 Bourgeau), corresponding to Dinehra bromoides, HBK., though that 

 seems to have been based upon specimens with the second flower less 

 developed than usual. Schaffner's specimens are smaller and decum- 

 bent, according in every respect with Dinehra repens, HBK. ; 534 

 Bourgeau is the same. There can be little hesitation in referi-ing 

 all to Lagasca's species. 



BouTELOUA ARiSTiDOiDES, Thurb. At Solcdad, Coahuila (1353), 

 and at San Luis Potosi (1062 Schaffner) ; 941 Parry & Palmer.* 



BuciiLOE DACTYLOIDES, Engelm. At San Luis Potosi (1004 and 

 1021 ScliafFner, the staminate and pistillate forms) ; 922 and 953 

 Parry & Palmer, 



Pappophoruji Wrightii. Flowering glume 9-nerved and 9- 



* A study of tlie material in the Gray Herbarium has led to the following 

 arrangement and identification of the species of Boutdoua. The sections are as 

 proposed by Mr. Bentham. Tlie synonymy is complicated, and some of Lagas- 

 ca's species yet remain uncertain, owing to his very brief and imperfect de- 

 scriptions. His D. barbata appears to belong to the section Chondrosium, and 

 B. juncifoUa and B. ovatn to Atheroporjon. 



§ 1. Chondrosium, Gray. Spikes one to several, linear or oblong, more or 

 less falcate, the usually very numerous spikelets pectinately crowded on one 

 side of tlie rhachis : terminal empty glume usually 3-awned. 



* Spike always solitary, 

 ■t- Lower glumes glabrous. 



1. B. TENUIS, Griseb. (in part). Mexico. See page 176. 



2. B. PROSTRATA, Lag. Western Texas and New Mexico to Mexico. See 

 page 176. 



3. B. SIMPLEX, Lag. Andes of South America. 



I- -1- Lower glumes villous. 



4. B. scoRPioiDES, Lag. Mexico. See page 176. 



* * Spikes usually 2 or more, 

 t- Spikes oblong-linear, very dense : lower glumes villous. 



5. B. niRSDTA, Lag. Pedicel of sterile glume glabrous. — Illinois to Texas, 

 Arizona, and Mexico ; Florida. See page 177. 



