GENUS 41. 



GRASS FAMILY. 



2OI 



41. POLYPOGON Desf. Fl. Atl. i : 66. 1798. 



Mostly annual grasses, with decumbent or rarely erect culms, flat leaf-blades and spike- 

 like panicles. Spikelets i-flowered; scales 3; the 2 outer empty, each extended into an awn; 

 third scale smaller, generally hyaline, short-awned from below the apex, subtending a palet 

 and perfect flower; palet shorter than the scale. Stamens 1-3. Styles short, distinct. 

 Stigmas plumose. Grain free, enclosed in the scale and palet. [Greek, in allusion to the 

 many long awns which resemble a beard.] 



About 10 species, widely distributed in temperate and warm regions, rare in the tropics. Type 

 species : Alopecurus Monspeliensis L. 



i. Polypogon Monspeliensis (L.) Desf. 

 Annual Beard-grass. Fig. 483. 



Alopecurus Monspeliensis L. Sp. PI. 89. 1753. 

 P. Monspeliensis Desf. Fl. Atl. i: 67. 1798. 



Culms 2 tall or less, erect from a usually de- 

 cumbent base, smooth and glabrous. Sheaths 

 generally shorter than the internodes, loose, 

 sometimes slightly scabrous; ligule \\"-^' long; 

 blades ii'-6' long, ii"-3" wide, scabrous, espe- 

 cially above; panicle i'-4' in length, dense and 

 spike-like, the branches i' in length, ascending; 

 spikelets crow r ded ; outer scales about i" long, 

 obtuse, slightly bifid, scabrous, bearing a more or 

 less bent awn 2"-$" long ; third scale much 

 shorter, erose-truncate, hyaline, bearing a delicate 

 awn about \" long, inserted below the apex. 



In waste places, Maine to Georgia, and in Texas, 

 mostly near the coast. Very abundant in western 

 North America, from British Columbia to Mexico. 

 Naturalized from Europe. Native also of Asia. 

 July-Sept. 



42. ARCTAGROSTIS Griseb. in Ledeb. Fl. Ross. 4 : 434. 1853. 



Perennial grasses with flat leaves and contracted panicle. Spikelets i-flowered. Scales 

 3; the 2 outer empty, unequal, somewhat acute, membranous; the third scale exceeding the 

 second, subtending a palet and perfect flower, obtuse ; palet obtuse, 2-nerved. Stamens 2 or 3. 

 Styles distinct, short. Stigmas plumose. Grain oblong, free, enclosed in the scale and palet. 

 Seed adherent to the pericarp. [Latin, signifying an arctic Agrostis-\ike grass.] 



A genus of 5 or 6 species, inhabiting arctic and sub- 

 arctic regions. Type species : Colpodium latifoliutr 

 R. Br. 



i. Arctagrostis latifolia (R. Br.) Griseb. 

 Arctagrostis. Fig. 484. 



Colpodium latifolium R. Br. Suppl. App. Parry's Voy. 



286. 1824. 

 A. latifolia Griseb. in Ledeb. Fl. Ross. 4: 434. 1853. 



Culms 6'-2 tall, erect, or sometimes decumbent 

 at the base, simple, smooth and glabrous. Sheaths 

 shorter than the internodes ; ligule 2" long, truncate ', 

 blades i'~7' long, i"-4" wide, usually erect, scabrous; 

 panicle il'-8' long, narrow, its branches i'-2' it 

 length, ascending or erect; spikelets ii"-2" long; 

 outer scales unequal, acutish, the lower about two- 

 thirds to three- fourths the length of the upper; third 

 scale obtuse, exceeding the second, hispid on the keel. 



Greenland to Hudson Bay and Alaska. Also in arctic 

 Europe and Asia. Summer. 



