34 



k GRAMINEiE. 



Spikelets broad; nerves of bracts dark green, mid-nerve curved inwards 



above ; wings broad, white LP. Canariensis. 



Spikelets narrow ; nerves of bracts pale green, mid-nerve straight from a 

 little above the base ; wings narrow, pale green . . . 2. P. Caroliniana. 

 Rudimentary bractlet 1 only ; thyrse from ovoid-oblong to oblong-cylindrical. 

 Spikelets ovate ; nerves of bracts dark green, mid-nerve curved inwards 

 from below the middle ; wings narrow, w T hite .... 3. P. minor. 

 Spikelets of secondary branches of the thyrse imperfect or abortive, giving a 

 gnawed appearance to the lower part of the thyrse; wing of bract termi- 

 nating in a horn 4. P. paradoxa. 



Spikelets all perfect : bracts wingless or only slightly winged, keeled ; annuals 

 or perennials. 



Annual ; 1 y 2 to 3 ft. high ; thyrse cylindrical, almost spikelike, mostly 2% to 

 4 in. long ; bracts keeled"; flower-enclosing bractlet abruptly acuminate. 



5. P. Lemmuni. 



Perennial ; stems 3 to 8 ft. high ; inflorescence usually purplish ; bracts 

 strongly keeled ; flower-enclosing bractlet acuminate. 



Thyrse oblong, 1 to 2 in. long, usually dense 6. P. amethystina. 



Panicle 3 to 6 or even 9 in. long, usually much interrupted or lobed .... 



7. P. arundinacea. 



1. P. Canariensis L. Canary-grass. Annual; stems erect, 1 to 

 3 ft. high, leafy; uppermost sheaths much inflated; ligule 2 to 3^ 

 lines long; blades 6 to 9 in. long, H to 5 lines wide; thyrse 1 to 1£ in. 

 long, | in. to f in. wide, ovoid, dense, uninterrupted; spikelets 2h to 3 

 lines long, laterally flattened, obovate, abruptly pointed; bracts sub- 

 equal, acute, broadly keeled from below the middle; keel nearly h line 

 wide, broadly white-margined, the mid-nerve curved inwards above; 

 empty bractlets 2, about 1 line long, narrow, smooth; flower-enclosing 

 bractlet about 2 lines long, pubescent when young, glabrous in age. 



Native of Europe, reported as occurring sparingly near settlements 

 in several localities within our limits. San Francisco, Bohinder. 

 Apr. The well-known " Canary -grass, a favorite bird-seed, much 

 cultivated in the south of Europe. 



2. P. Caroliniana Walt. Southern Canary-grass. Annual; 

 stems slender, erect, 1 to 2 ft. high; uppermost sheaths somewhat 

 inflated; ligule 1^ to 2 lines long, decurrent, obtuse or truncate, 

 broad, completely enveloping the stem and folded over itself; blades 

 \h to 4£ in. long, 2^ to lines wide, acute, smooth; thyrse 1 to 2 in. 

 long, ovoid; spikelets 2£ to 3 lines long; bracts acute, the mid-nerve 

 straight from a little above the base, nerves and keel concolorous, pale 

 green; empty bractlets about 1 line long, pubescent; flower-enclosing 

 bractlet acuminate, pubescent. 



Native of the southeastern States, and apparently not indigenous 

 with us. Oakland, Bolander; Araquipa Raneho, Vacaville, Jepson. 

 Apr.-May. Much less common than is generally supposed, P. minor 

 being often mistaken for it, both in the field and in herbaria. 



3. P. minor Retz. Small Caxarv-oeass. An erect, glabrous, 

 leafy annual, from 1\ in. to 3 ft. high, according to locality and 

 season, branched sometimes from every node except the uppermost; 

 upper sheaths sometimes glaucescent, much dilated, with a broad, 

 scarious margin; ligule large, 1 to 3 or even 4£ lines long, entire, 

 obtuse; blades 4£ to 13 in. long, 4.] to lh lines wide; in small speci- 

 mens only 2 to 3 in. long, and 3 lines wide; thyrse very dense and 



