272 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



12. HORDEAE. 



Spikelets solitary at each node of the continuous rachis__105. Lolium (p. 396). 

 Spikelets in 3's at each node of the articulate rachis 106. Hordeum (p. 396). 



13. BAMBOSEAE. 



Stems climbing or clambering. 



Spikelets 2 to several-flowered, racemose 107. Arthrostylidiuin (p. 397). 



Spikelets 1-flowered, in small panicles 108. Chusquea (p. 400). 



Stems erect. 



Spikelets 1-flowered, in a long dense terminal panicle ; culm herbaceous. 



109. Planotia (p. 400). 



Spikelets several to many-flowered, sessile in clusters, these somewhat 



remote on a common axis; culms woody 110. Bambos (p. 401). 



1. TRIPSACUM L. 



Spikelets unisexual; pistillate spikelets solitary, embedded in the joints of a 

 thickened cartilaginous articulate rachis, the indurate first glume covering the 

 recess in the rachis, the joints readily separating at maturity ; staminate spike- 

 lets in pairs at the joints of the continuous upper segment of the same rachis, 

 this falling as a whole after anthesis. Stout perennials. 



1. Tripsacum dactyloides (L.) L. Syst. Nat. ed. 10. 2: 1261. 1759. Gama gbass. 



Coix dactyloides L. Sp. PI. 972. 1753. 



Tripsacum monostachyum Willd. Sp. PI. 4: 202. 1S05. 



Culms sparingly branching, about 2 meters tall, in large clumps ; blades flat, 

 up to 3 cm. wide ; inflorescence of 1 to 3 erect spikes. 



Shady ravines and moist ground at low altitudes, central and southeastern 

 United States, through the West Indies to South America. Originally described 

 from America, no definite locality given. 



Haiti, Santo Domingo, and Trinidad. _-_--___ __ 



2. COIX L. 



Spikelets unisexual; pistillate spikelets 2 or 3 together, 1 fertile and 1 or 2 

 rudimentary, inclosed in a bony beadlike involucre (morphologically a subtend- 

 ing leaf sheath) ; staminate spikelets approximate in 3's (the third sometimes 

 obsolete) on a slender rachis forming a short raceme, the rachis protruding 

 from the orifice of the involucre, these ultimate inflorescences borne on the 

 ends of numerous branches. Broad-leaved perennials. 



1. Coix lacryma-jobi L. Sp. PI. 972. 1753. Job's teabs. 



Freely branching, 1 meter or more tall, the cordate clasping blades 2 to 3 cm. 

 broad, the " beads " 8 to 10 mm. long. 



Moist ground and waste places, especially near dwellings, throughout tropical 

 America, cultivated as an ornamental and for the ivory or grayish beads ; often 

 escaped. Called also " Christ's tears," " camandula," and " lagrimas de Job." 

 Originally described from the East Indies. 



Common in the West Indies and to be found on probably all of the islands. 



3. IMPERATA Cyrillo. 



Spikelets all perfect, awnless, all pedicellate, articulate below the glumes, the 

 rachis not disjointing, the slender racemes in a narrow spikelike panicle; glumes 

 membranaceous, densely clothed with long silky hairs. 



Panicle rarely over 10 cm. long ; spikelets 4 mm. long 1. I. brasiliensis. 



Panicle and blades elongate ; spikelets 3 mm. long 2. I. contracta. 



