364 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



61. STREPTOCHAETA Schrad. 



Spikelets subsessile on a slender flexuous axis, perfect, one of the sterile 

 lemmas extending into a long smooth filiform tendril-like coiled awn, the tips 

 of all the awns apparently attached to the prolonged summit of the axis; 

 stigmas 3. An anomalous genus of doubtful relationship. 



1. Streptochaeta spicata Schrad. ; Nees, Agrost. Bras. 537. 1829. 



An erect perennial, with broad thin elliptical blades and spikes of distant 

 appressed elongate-conic spikelets with tendril-like awns. 



In the shade of the forest, Brazil, whence originally described, to Trinidad 

 (Caparo Forest, Broadway 4929). 



62. PHALARIS L. 



Spikelets strongly compressed, the keeled glumes exceeding the subindurate 

 oerfect floret and attached sterile lemmas. 



1. Phalaris canariensis L. Sp. PI. 54. 1753. Canary geass. 



An erect annual with flat blades and ovoid heads, the papery imbricate spike- 

 lets whitish with green stripes. 



Originally described from Europe, but widely distributed as a weed of waste 

 places. Found in Bermuda and Cuba (Habana). 



63. ANTHOXANTHUM L. 



Glumes very unequal; sterile lemmas awned, exceeding the small awnless 

 perfect floret. 



1. Anthoxanthum odoratum L. Sp. PL 28. 1753. Sweet vernal grass. 



A tufted fragrant perennial with flat blades and loosely spikelike panicles 

 commonly about 5 cm. long. 



A native of Europe, occasionally cultivated in the United States and escaped 

 from cultivation. Introduced in the vicinity of Cinchona, Jamaica. Originally 

 described from Europe. 



64. ARISTIDA L. 



Spikelets in close or open panicles ; glumes acuminate ; lemma convolute, 

 subindurate with a pointed callus and bearing from the apex a trifid awn. 



Plants annual 1. A. adscensionis. 



Plants perennial. • 



Lateral awns minute or wanting 9. A. scabra. 



Lateral awns about as long as the middle one. 



Panicle a dense bristly spike ; fruit with a twisted neck 1 cm. long. 



7. A. spiciformis. 

 Panicle open or contracted, not a dense spike ; neck of fruit short or 

 none. 

 Plants robust, more than 1 meter tall ; blades as much as 50 cm. 



long and 4 mm. wide, very scabrous 8. A. erecta. 



Plants slender, usually less than 50 cm. tall ; blades not over 2 

 mm. wide, smooth or slightly scabrous. 

 Awns or some of them 2 to 3 cm. long ; blades sparsely pilose on 



the upper surface toward the base 6. A. portoricensis. 



Awns' mostly less than 1.5 cm. long. 



Culms usually widely spreading ; spikelets crowded on the 

 short panicle branches 2. A. cognata. 



