26 



FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



is usually digitate, but both these cases have frequent exceptions. 

 Finally as all have, with a small variation in size only, the same 

 fruiting glumes and grain, it seems wisest to consider all as forms of 

 one variable species. 



Syntherisma filiforme (L.) Nash. Bull. Torr. Bot. Club, 22:420. 

 Panicum filiforme L. 



Inflorescence fasciculate-panicled, long exserted, of 4-8 racemes;, 

 axis 1-3 cm. long, striate, glabrous. 

 Racemes erect or ascending, filiform, 4-12 

 cm. long, rachis somewhat flexuous, 

 3-angled, hispidulous on the margins. 

 Spikelets in pairs or in 3's, .7x1.7 mm. r 

 ellipsoid, abruptly acuminate. First glume 

 wanting; second ^ the length of the spike- 

 let, ovate with blunt apex, 3-nerved, mar- 

 gins- and internerves pubescent with 

 appressed, gland-tipped hairs; third slightly 

 shorter than the floral glume, 7-nerved, the 

 margins and first and second internerves 

 on each side pubescent with gland-tipped 

 hairs; floral glume 1.7 mm., chestnut with 

 white margins, papillo-striate; palea equal 

 and of like texture. Grain translucent 



creamy white, oblong with subacute base and rounded apex, .5 x i.i 



mm. ; in section convexo-concave. 



Hab Chichankanab, Gaumer 2250. 



Yucatan and West Indies specimens have spikelets mostly in 3*5. 



Syntherisma setosum (Desv.) Nash Bull. Torr. Bot. Club 25: 300. 



Digitaria setosa Desv. 



Inflorescence panicled, long-exserted, of 6-18 racemes, lower- 

 most usually whorled; axis 2-5 cm., rarely to 20 cm. long, striate, 

 glabrous. Racemes spreading, filiform, 

 5-10 cm. long; rachis 3-angled, hispidu- 

 lous on the margins. Spikelets in pairs 

 .7 x 2.4 mm., lanceolate, acuminate. First 

 glume wanting; second ^ the length of 

 the spikelet, lanceolate, acuminate, 

 3-nerved, villous at the summit; third 2.4 

 mm., prominently 5-nerved, villous on the 

 margins and summit; floral glume nearly 

 equal to third, greenish purple, papillo- 

 striate; palea equal and of like texture. 

 Grain translucent pinkish white, ellipsoid. 

 .5 x 1.25 mm. ; in section convexo-concave. 



Hab. San Felipe, Gaumer 1405, 

 2490, Chichankanab 1524, Pocoboch 2494. 



Yucatan specimens have longer pan- 

 icles of more scattered racemes than our specimens from subtrop- 

 ical Florida and St. Croix. 



