86 
CLVII. GRAMINEiE (Stapf). 
\Rhytachne. 
solitary, fragile, from the uppermost sheath, erect, straight, quite 
glabrous, usually pale-greenish ; joints linear, 2 to over 3 lin. long, 
more or less clavate and hollow upwards, slightly concave on. the 
inner side, more or less rounded on the back, with 2 prominent and 
several faint nerves, slightly rough, disarticulating horizontally, 
with a ciliolate rim round the scar ; pedicels linear, tapering and 
twisted upwards, contiguous with the joints, much compressed, 
rigidly ciliate, middle nerve prominent, as long as or longer than 
the joints. Sessile spikelet linear-oblong, shortly acuminate, 2J lin. 
long (excluding the awns), callus minute. Lower glume subcoria- 
ceous, terminating with 2 mostly unequal bristles, the longer of 
which may be up to over 3 lin. long, transversely rugose (rugae 5-7, 
laterally projecting) with longitudinal ribs, smooth towards the tips, 
keels narrowly winged, ciliolate above, nerves 6-7, fairly distinct. 
Upper glume hyaline, membranous, linear in profile, acute, with a 
fine terminal bristle, up to 3 lin. long, 3-nerved. Lower floret barren : 
valve lanceolate, subacute, somewhat shorter than the glumes, 
hyaline, 2-nerved, with a narrow nerveless valvule. Upper floret : 
* valve linear-lanceolate, acute, about 1 lin. long, delicately hyaline, 
faintly 1 -nerved, with a valvule less than half its length. Anthers 
J-J lin. long. Stigmas J lin. long. Pedicelled spikelet usually 
represented by 2 fine stiff unequal scabrid awns, the longer of which 
may be up to over 2 lin. long. — Rhytachne triseta, Hack, in DC. 
Monogr. Phan. vi. 275 ; Durand & Schinz, Consp. FI. Afr. v. 700. 
Lepturopsis triaristata, Steud. Syn. Pl. Glum. i. 358. Rhytidachne 
triseta , K. Schum. in Engl. Pfl. Ost-Afr. C. 97. Rhytidachne triaristata , 
K. Schum. l.c. Ischcemum elionuroides, Munro MS. ex K. Schum. l.c. 
Upper Guinea. Sierra Leone : Los Islands, Jardin. French Guinea : Segou, 
Chevalier, 2329 ! Timbo, Pobeguin, 1765 ! 
North Central. Upper Ubangi River : plateau of the Ungourras, 1500 ft. 
Chevalier, 6142 ! 
Nile Land. Bongo : Gir, Schweinfurth, 2485 ! 
Hackel describes this grass as perennial with extravaginal innovations. I 
find all the specimens seen by me to consist of culms terminating with an 
inflorescence as do also the branches, if there are any present, and I must there- 
fore consider the grass as annual. 
6. R. gracilis, Stapf in Journ. de Bot., 1905, 98, and Pobeg. Ess. 
FI. Guin. Fr. (1906) 219. Annual, not forming tufts though growing 
in close association. Culms slender, up to 16 in. high, 2-3-noded, 
compressed below and enclosed at the base in a short sheath, 2 upper 
internodes long-exserted, glabrous like the whole plant. Leaf- 
sheaths smooth, those at the base much compressed, keeled, about 
1 in. long ; ligules short, ovate, subauriculate, minutely hairy on 
the back ; lower and intermediate blades filiform, tightly com- 
plicate, 2-3 in. long, J lin. wide when folded, the uppermost seti- 
form and short. Racemes solitary, erect, straight or more or less 
flexuous, up to 4 in. long ; joints linear, clavate and hollow above, 
