GENERA OF GRASSES OF THE UNITED STATES. 133 



Coleanthus xuhtiUx (Tnitl.) Seidel (fig. 71), introduced from 

 Europe, grows on mud flats along the Columbia River, where it was 

 collected by Howell (on Sauvies Island, Oreg.) and by Suksdorf 

 (western Klickitat County, Wash.). 



Mibora minima (L.) Desv. has been found at Plymouth, Mass. 

 This, the only species of the genus, is a low annual, differing from 

 Coleanthus and Phippsia in having glumes longer than the lemma, 

 the very small spikelets in simple spikes. Introduced from Europe. 



59. CINNA L. 



Spikelets 1 -flowered, disarticulting below the glumes, the rachilla 

 forming a stipe below the floret and produced behind the palea as a 

 minute bristle; glumes equal, 1-nerved; lemrria similar to the glumes, 



FIG. 71. Coleanthus nubtilis. Plant, X 1 ; lemma and palea and two views of spikelet 



with ripe caryopsis, X 20. 



nearly as long, 3-nerved, bearing a minute, short, straight awn just 

 below the apex ; palea apparently 1-nerved, 1-keeled. 



Tall perennial grasses, with flat blades and paniculate inflorescence. 

 Species three, North America and northern Eurasia, two in the 

 United States and one in Mexico and southward. 



Type species: Cinna arundinacea L. 



Cinna L., Sp. PI. 5, 1753; Gen. PI., ed. 5, 6. 1754. A single species is 

 described. 



Abobi Arlans., Fam. PI. 2: 31, 511. 1763. Based on "Cinna Lin." 



Cinnastrum Fourn., Mex. PL 2: 90. 1886. Two species are given, C. miliaceum 

 and ('. ])<>u<' forme, both referable to Ginna poaeformis (H. B. K.) Scribn. and 

 Merr. 



The prolongation of the rachilla is less than 0.5 mm. in our 

 species, but in Cinna poaeformis of Mexico it is half as long as the 

 palea. The palea is 1-nerved in C. arundinacea. In C. poaeformis 

 the 2 nerves are close together but distinct. In C . latifolia the palea 

 is apparently 1-nerved, but the 2 nerves separated when the palea is 

 split along the keel. 



