122 



GRAMINEAE. 



VOL. I. 



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

 Racemes short, \'-A,' long; spikelets less than i" long. 

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

 Rachis of the racemes with the lateral angles broadly winged. 

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



Leaves pubescent ; second scale J/> as long as the spikelet or less. 

 Leaves glabrous ; second scale nearly as long as the spikelet. 

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

 Spikelets about 1^4" long; third scale with nerves mostly hispid. 



Spikelets about 



long ; third scale with the nerves smooth. 



1. S. filiforme. 



2. S. 1'illosum. 



3. S. serotinum. 



4. 5". Ischaemum. 



5. -S 1 . sangiiinale. 



6. S. 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 l'-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 -villa sum Walt. Fl. Car. 77. 1788. 



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

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

 i4"~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*5, 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. 



Fig. 280. 



Late-flowering Finger-grass. 



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 pairs, in 2 rows 

 on one side of a flat and winged rachis less than i"" 

 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. 



