15 



Jour., Bom. Nat. Hist. Soc, Vol. XXXIV, No. 1 [March 1, 1930. 



w 



b. Spikelets in panicled racemes, 2-flower- 



ed, awned (vol. 32, 288) ... ... 24. Spodiopogon. 



B. Group PolliniastrcB . — Racemes digitate, 

 rarely solitary ; spikelets 1-2-flowered ; 

 awn from the sinus of the 2-fid or 2- 

 dentate floral glume; spikelets dorsally 

 compressed ; callus short, obtuse (vol. 32, 

 289) ... ... ... 25. Eulalia. 



S ub -tribe : Andropogonince. — Spikelets of 

 each pair different in sex and frequently 

 also in shape and size, or if those of some 

 pairs of a raceme are alike in sex, then 

 both male or neuter ; fertile spikelets 1- 

 flowered (Genera 26^41). 



A. Racemes in more or less compound espa- 



theate panicles ; pedicels without a 

 translucent middle line (Genera 26- 

 29). 

 Group Sorghastrce. — Pedicelled spikelets 

 male, neuter or suppressed (including 

 the pedicel in Cleistachne) ; awn from 

 the sinus of the 2-fid floral glume. 

 i. Spikelets dorsally compressed, at least 

 when in flower; lower involucral glume 

 of the fertile spikelets firmly charta- 

 ceous to coriacous. 



a. Spikelets in threes, one of them fertile, 



or in racemes of 2-8 pairs ; the 

 pedicelled male, neuter, or if quite 

 suppressed, then at least the pedicels 

 present (vol. 32, 290) ... ... 26. Sorghum. 



b. Spikelets solitary (vol. 32, 408) ... 27. Cleistachne. 

 ii. Spikelets laterally more or less com- 

 pressed. 



a. Racemes of many pairs of spikelets ; 



primary branches of panicles in 



whorls of 6-20 (vol.32, 408) ... 28. Vetiveria. 



b. Racemes usually reduced to 1 sessile 



hermaphrodite and 2 pedicelled 

 male or barren spikelets, rarely of 

 2 or more but always few pairs 

 (vol. 32, 410) ... ... ... 29. Chrysopogon. 



B. Racemes not in compound espatheate 



panicles or if so (Capillipedium) , then 

 the pedicels* with a translucent middle 

 line (Genera 30-41). 

 i. Fertile floral glume awned from low down 

 on the back. 

 Group Arthraxonastrce . — Sessile spike- 

 lets convex on the back and rounded on 

 the sides, often muriculate, particularly 

 along the sides ; pedicelled usually 

 rudimentary or 0, rarely male ; racemes 

 digitate (vol. 32, 416) ... ... 30. Arthraxon 



ii. Fertile florel glume awned from the sinus 



of a 2-fid or 2-dentate valve or continuing 



the more or less stipitiform floral glume 



(Genera 31-41). 



a. Margins of the lower involucral glume 



of the fertile spikelet inflexed and 



the glume therefore sharply 2-keeled 



more or less all along with a short 



obtuse callus, rarely the keels 



rounded off downwards with the 



margins subinvolute, but then the 



