FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



palea and staminate flower; fruiting glumes 1.6x4.5 mm., lanceolate- 

 ovate, acute, smooth and shining. Grain light brown, obovoid- 

 oblong, 1x2 mm.; in section unsymmetrical plano-convex. 



Hab. Grassy edge of sandy beach, west shore Island of Cozu- 

 mel, at the portage to Laguna, Colombia, Jan. 7, 1895, Millspaugh^ 

 Armour Exped. $o(Stenotaphrum Americanum Schrank, Field Col. Mus. 

 Bot. 1:10); Chichankanab, Gaunter 1500. 



OLYRA L. Syst. Ed. TO, 1261. 



Inflorescence monoecious ; spikelets i-flowered, the staminate 

 spikelets upon the lower portion of a simple panicle, without empty 

 glumes; pistillate spikelets much larger, with 2 empty, herbaceous, 

 awned glumes; fruiting glumes, osseous, white and shining. 



Olyra semiovata Trin. Diss. 2:249. 



Panicle long-exserted, contracted, 8-14 cm. long, 2 cm. wide, 

 axis and rachis scabrous. Staminate spikelets 

 mostly in pairs on slender scabrous pedicels 

 on the lower branches and on the lower part of 

 the upper pistillate branches; floral glume 6 

 mm. (excluding awn), lanceolate, 3-nerved, 

 nerves hispidulous above, awn 2 mm. ; palea, 

 acute, nerves hispidulous above. Pistillate 

 spikelets 4x8 mm. (excluding awns), green, 

 ovate, on scabrous clavate pedicels. First 

 and second glumes ovate, oblong, awned, 

 7-nerved, scabrous especially on the nerves 

 above; awn of first 8-12 mm., of second 4-5 

 mm. long, hispidulous; fruiting glumes 4x7 

 mm., old ivory white, shining, oval, subacute; 

 floral glume white silky pubescent at base 

 and margins. Mature grain not seen. 



Hab. Common at Chichanakanab, Gau- 

 nter 1389, Pocoboch 2372. 



Yucatan specimens have fruiting glumes somewhat shorter and 

 more densely pubescent than typical forms. 



ARISTIDA L. Sp. PL 82. 



Inflorescence paniculate. Spikelets i -flowered, perfect, rachilla 

 articulated above the empty glumes and produced into a hard obconi- 

 cal, hairy callus below the floral glume, but not extending beyond it. 

 Glumes 3, first and second empty, the floral glume 3-nerved, silicate 

 roughened, closely rolled around the palea and flower and terminating 

 in a trifid or (Streptachne) single awn. Grain elongated, tightly 

 enclosed by the indurated fruiting glume, but free from it. Stamens 3. 



Awn trifid, grain dorsally compressed: 

 Floral glume 8 mm. siramineous 

 Floral glume 6.5 mm. plum-color 



Awn single, grain terete: 



Floral glume 10 mm. stramineous 



Floral glume 12 mm. mottled dark purple 



bromoides. 

 nigrescens. 



scabra. 

 tenuis. 



