The Flora of the Cayuga Lake Basin 85 



Along the coast from N. H. to Fla. and Tex., and inland about the Great Lakes. 

 Found also in VV. I. Perhaps influenced by the salt springs in cent. N. Y. 



A form with glabrous sheaths (forma laevigata Wiegand) occurs occasionally, but 

 has not been found within the limits of this flora. 



42. Panicum L. 

 a. Basal leaves, if present, not differing from the cauline leaves. 

 b. Plant hairy. 



c. Panicle not nodding ; spikelets 4 mm. long or less. 



d. Spikelets acuminate, 2-4 mm. long, lanceolate or ovate-lanceolate ; first empty 

 glume acute, acuminate, or subaristate. 

 e. Panicle large and broad when mature ( 15—40 cm. by 15-30 cm.), the 

 branches spreading; leaves 5-10 mm. wide, finely and densely villous. 

 /. Spikelets all or nearly all long-pedicelled, 2-3 mm. long ; panicle tardily 

 exserted, its lower branches mostly included during anthesis. 



1. P. capillar e 



f. Spikelets, except the terminal one, subsessile, 2.5-4 mm. long; panicle 

 exserted in anthesis. la. P. capillare, 



var. occidentalc 

 e. Panicle smaller (10-20 cm. by 5 cm.), elliptical, the branches stiff and 

 ascending; leaves 2-5 mm. wide, rather loosely villous. 



2. P. flexile 



d. Spikelets obtuse or apiculate, 1.3-2.2 mm. long, elliptic to oval ; first empty 



glume obtuse to subacute. 



e. Panicle broad (15-30 cm. long, or shorter in smaller plants, 12-20 cm. 



wide) ; spikelets 1.3-2 mm. long; leaf blades villous on both surfaces, 



long and narrow, 4-7 (8) mm. wide. 



/. Panicle long-exserted ; spikelets mostly pedicelled ; pulvini at base of 



branches of the panicle hairy. [P. philadclphicum] 



f. Panicle short-exserted or the base included; spikelets more spicate- 

 racemose on the branches ; pulvini glabrous, except sometimes on the 

 upper side. 3. P. Tuckermani 



e. Panicle narrower, elliptic-oval, small (10-20 cm. long, 7-10 cm. wide) ; 

 spikelets larger, 1.8-2.2 mm. long; leaf blades almost or quite glabrous, 

 shorter, broader, (5) 6-10 mm. wide; plant much branched, with many 

 axillary panicles. 4. P. Gattingeri 



c. Panicle nodding; spikelets 5 mm. long. 5. P. miliaceum 



b. Plant glabrous. 

 c. Plant annual, much branched, decumbent; culms compressed, succulent; spike- 

 lets elliptic-lanceolate, acute. 6. P. dichotomiflorum 

 c. Plant perennial, strict, erect, unbranched; culms rigid, terete; spikelets ovate, 

 acuminate. 7. P. virgatum 

 a. Basal leaves short, broad, and ovate, forming a winter rosette. 



/>. Leaves elongate-linear, erect, narrow (3 mm. wide), almost twenty times as long 

 as wide, nearly all basal; plant low and tufted; spikelets tending to be con- 

 tracted at the base. 

 c. Spikelets 3-3.5 mm. long, acute or subacuminate, glabrous or nearly so; foliage 



nearly glabrous. 8. P. depauperatum 



c. Spikelets 2-2.5 mm. long, obtuse or obtusish. 

 d. Sheaths pilose; spikelets pubescent. 9. P. line ari folium 



d. Sheaths glabrous; spikelets almost glabrous. 9a. P. linearifolium, 



var. Wemeri 

 b. Leaves linear-lanceolate or broader, not conspicuously elongated, scattered on 

 the culm; plant less tufted, usually taller and more open; spikelets not con- 

 tracted below. 



