17b. Blade 20 to 40 mm. wide 



100. Pcnnisctum spp. — Gahi No. 1 Millet 



Leaves rolled in bud-shoot ; sheath somewhat flattened, slightly rough 

 or hairy at top, split with overlapping margins hyaline or hairy; auricles 

 absent; collar broad, may be divided, hairy at least on margins; ligule a 

 fringe of hairs, 3 to 6 mm. long; blade 20 to 40 mm. wide, smooth to 

 slightly rough above and long hairy near base, smooth to rough below, 

 margins rough and hyaline. Inflorescence — a stiff, cylindrical, very 

 dense panicle. May be cultivated in southern part for forage. 



18a. Blade long hairy above and below 



101. Panicum villosissimum — White-haired Panicgrass 



Leaves rolled in bud-shoot; sheath loose, round, long hairy, split with 

 overlapping hairy margins; auricles absent; collar broad, hairy, ligule 

 a fringe of hairs, 3 to 5 mm. long ; blade 5 to 1 2 mm. wide, long hairy 

 above and below, margins rough. Inflorescence- — a loosely flowered 

 panicle with branches stiffly ascending or spreading. Massachusetts south. 

 Dry or sterile soil. 



1 8b. Blade not long hairy above and below 



102. Panicum virgatum — Switchgrass 



Leaves rolled in bud-shoot; sheath round, smooth or somewhat hairy, 

 split with margins overlapping and at least one hairy ; auricles absent ; 

 collar medium broad to broad, may be divided, sometimes hairy on mar- 

 gins; ligule a fringe of hairs, 3 to 6.5 mm. long, may be fused at base; 

 blade 7 to 15 mm. wide, mostly smooth above but may be long hairy 

 near base, smooth below, margins rough. Inflorescence — an open, widely 

 spreading panicle. Common throughout. Open ground and brackish 

 marshes. 



GROUP 8 



la. Ligule 2 mm. or less long 2 



1 b. Ligule more than 2 mm. long 12 



2a. Blade 5 mm. or less wide 



103. Triplasis purpurea — Purple Sandgrass 



Leaves rolled in bud-shoot ; sheath round, rough, purplish, split with 

 overlapping margins, hairy at nodes; auricles absent; collar medium 

 broad, hairy on margins; ligule a fringe of hairs, 1 to 1.4 mm. long; 

 blade 3 to 4.5 mm. wide, very rough above and below, margins rough 

 with a few long hairs near base. Inflorescence — a short, few-branched, 

 spreading panicle. Maine south. Dry sand. 



2b. Blade more than 5 mm. wide 3 



33 



