151 



the glumes in structure and nervation, the upper firmer, at length 

 rigid, often chartaceous to crustaceous, awnless, very rarely mucronate. 

 Paspalum; Digitaria; Panicum; Oplismenus; Axonopus; Setaria; 

 Pennisetum ; Stenotaphrum ; Tricholaena ; Melinis. 



SERIES II. 



Mature spikelets breaking up, leaving the persistent or sub- 

 persistent glumes on the pedicel, or if falling entire, then not con- 

 sisting of 2-heteromorphous florets as in Series I. 



Tribe 3. Arundinelleae. Florets 2, heteromorphous, the lower 

 awnless, male or barren. Rachilla not continued beyond the upper 

 floret. Lower valve awnless, rather resembling the glumes ; upper 

 generally (always in the African species) awned, at length firm or 

 hard ; awn from the sinus l^etween 2 sometimes minute or bristle-like 

 lobes, rarely from the entire, obtuse tip, usually kneed and twisted 

 below the knee. 



i\j.'undinella ; Trichopteryx ; Tristachya. 



Tribe 4. Avene^e. Florets 2 to many, all alike (except the upper- 

 most which often are gradually reduced) or more or less heteromorj^hous 

 (shghtly in Holcus ; ChcTetobromus ; and sometimes in xVira, very dis- 

 tinctly in Anthoxanthum). Glumes generally hyaline or scarious and 

 shining. Valves membranous or sub-herbaceous with hyaline shining 

 margins, 5 or more nerved, rarely 3-nerved (with the side nerves 

 delicate and not sub-marginal) ; awn, if present, from the back or 

 from a sinus, or from between bristles, kneed and usually twisted 

 below the knee (See Koeleria). 



Anthoxanthum ; Koeleria ; Avenastrum ; Pentaschistis. 



Tribe 5. Arundinese Florets 2 to many, enveloped by very long 

 hairs, springing either from a long and slender callus or from the back 

 of the valves. Glumes and valves membranous, often hyaline, awnless 

 or minutely awned fi'om the tips. 



Phragmites. 



Tribe 6. Agrostege. Floret 1. Rhachilla not continued beyond 

 the floret or only as a more or less distinct jjoint or bristle. Valve 

 membranous (in South African speciesj or thinly herbaceous, not or 

 hardly changed when mature, usually truncate, S-ver}^ rarely o-nerved, 

 all the nerves or the outer side nerves often slightly excurrent, parallel 

 or at least not anastomosing ; awn if present, from the back, rarely from 

 the truncate tip. 



Polypogon ; Agrostis ; Calamagrostis, 



Tribe 7. Stipete. Floret 1. Rhachilla not continued beyond the 

 floret. Valve hardening when mature, tightly enveloping the fruit; 

 nerves joining or closely approaching at the tip ; awn terminal, rarely 0. 



Aristida ; Stipa. 



