122 



GRAMINEAE. 



VOL. I. 



Rachis of the racemes wingless ; first scale of spikelet wanting, or rudimentary. 



Racemes short, i'-4' long; spikelets less than i" long. i. 5 1 . filiforme. 



Racemes exceeding 4' long, rarely shorter; spikelets over i" long. 2. S, villosum. 



Rachis of the racemes with the lateral angles broadly winged. 

 Pedicels terete, glabrous or nearly so ; first scale wanting. 



Leaves pubescent; second scale l /2 as long as the spikelet or less. 3. S. serotinum, 



Leaves glabrous ; second scale nearly as long as the spikelet. 4. S. Ischaemum. 



Pedicels sharply 3-angled, the angles strongly hispidulous ; first scale minute. 



Spikelets about IJ4" long; third scale with nerves mostly hispid. 5. S. sangiiinale. 



Spikelets about 1)4" long; third scale with the nerves smooth. 6. 5. marginatum. 



i. Syntherisma filiforme (L.) Nash. Slender Finger-grass. Fig. 278. 



Panicum filiforme L. Sp. PI. 57. 1753. 

 Digitaria filiformis Koel. Descr. Gram. 26. 1802. 

 Syntherisma filiformis Nash, Bull. Torr. Club, 22 : 420. 



1895- 



Culms erect, i-4 tall, slender, smooth. Sheaths 

 hirsute; blades i'-8' long, "-2" wide, erect, hirsute or 

 glabrous on the lower surface, rough on the upper; 

 racemes 2-5, filiform, i'-4' long, approximate at the 

 summit of the culm, erect or nearly so; rachis 3-angled, 

 very slender, not winged; spikelets less than i" long, 

 elliptic, pubescent, in pairs, occasionally in 3's; first 

 scale rarely present ; second three-fourths as long as 

 or equalling the third, which equals the fourth. 



Dry sandy soil, New Hampshire to Michigan, south to 

 North Carolina and Oklahoma. July-Sept. Wire-grass. 



2. Syntherisma- villosum Walt. Southern 

 Slender Finger-grass. Fig. 279. 



Syntherisma villosum Walt. Fl. Car. 77. 1788. 



Culms densely tufted, 6'-4i tall ; sheaths, at 

 least the lower ones, hirsute; blades 3'-io' long, 

 ii"-3" wide, hirsute on both surfaces; racemes 

 2-8, usually exceeding 4' long, rarely shorter, 

 erect or ascending; spikelets over i" long, elliptic, 

 usually in 3's, the first scale wanting, the second 

 3-nerved, the fourth scale deep chestnut brown 

 at maturity. 



Sandy soil, Virginia to Missouri, south to Florida 

 and Texas. June-Oct. 



3. Syntherisma serotinum Walt. 

 Late-flowering Finger-grass. Fig. 280. 



Syntherisma serotinum Walt. Fl. Car. 76. 1788. 

 Panicum serotinum Trin. Gram. Panic. 166. 1826. 



Culms slender, erect, often creeping and branching 

 at the base, 8'-24' tall, smooth and glabrous ; sheaths 

 about one-half as long as the internodes, pilose with 

 long spreading hairs; blades linear-lanceolate to 

 lanceolate, i'-4' long, 2'' '-4" wide, acuminate, pilose 

 on both surfaces ; inflorescence composed of 2-6 

 i-sided slender erect or ascending spike-like racemes 

 i '-4*' long, arranged singly, in pairs, or scattered 

 and approximate ; spikelets numerous, oval, about I" 

 long and one-half as broad, acute, in pair's, in 2 rows 

 on one side of a flat and winged rachis less than V 

 wide; first scale wanting, the second about one-half 

 as long as the spikelet, 3-nerved, the third scale 7- 

 nerved, both appressed-pubescent on the margins. 



Fields and roadsides, southern Pennsylvania and 

 Delaware to Florida and Mississippi. 



