624 
CL VII. GRAMINEJE (Stapf). 
[. Acroceras . 
Lower Kasai river, Vanderyst, 4774 ! Mokaba, Vanderyst, 3611 ! Kisantu, 
Gillet, 460 ! 581 ! Angola : Pungo Andongo ; in thick damp woods, climbing 
with aerial roots, on Calemba Island in the Cnanza river, Welwitsch, 7429 ! 
Tropics of both hemispheres. 
2. A. maerum, Stapf. Perennial, up to over 2 ft. high from a 
slender creeping rhizome with extra vaginal innovations. Culms 
slender, ascending, or prostrate at the base and covered there with 
short papery to membranous cataphylls and the remains of half- 
decayed sheaths or bared at length by their decay, above this base 
6- to many-noded, sparingly branched, the upper internodes long- 
exserted, all terete, prominently striate, glabrous and smooth. Leaf- 
sheaths subherbaceous, terete, moderately tight, ciliate, other- 
wise quite glabrous, or pubescent with minutely tubercle-based 
hairs, smooth ; ligules reduced to a ciliolate rim sometimes quite 
obscure ; blades linear from a slightly rounded to subcordate and 
semiamplexicaul base, tapering to a slender subcallous point, 2^-8 in. 
by J-4 lin., or the lower sometimes still shorter, flat, subsucculent, 
somewhat rigid (at least the upper), obliquely erect, very pale green, 
glabrous or rigidly ciliate at the rounded base, rarely loosely 
pubescent, margins finely cartilaginous, smooth below, rough 
upwards, or smooth almost throughout, midrib and primary lateral 
nerves (3-4 on each side) fine, distinct only below, with 3-4 secondary 
nerves in the intervals, cross-veins short, sometimes very obscure. 
Panicle long-exserted, scanty, up to 8 in. long, of 5-1 erect or spread- 
ing spiciform secund branches, widely distant on a very slender 
subterete or towards the lower nodes semiterete and channelled or 
in the upper part triquetrous and scabrid common axis or the 
inflorescence reduced to a single interrupted spiciform raceme ; 
branches villosulous at their insertion, the longest up to 2J in. long, 
triquetrous at least upwards, with scaberulous or downwards smooth 
angles and a flat or convex back, — -J lin. wide, and an acutely keeled 
face, bearing at the nodes (2-4 lin. distant) from the base (rarely 
from some distance above it) mostly paired spikelets ; pedicels stiff, 
angular, scaberulous, appressed, with truncate tips, one very short, 
the other up to 1-2 lin. long. Spikelets oblong, shortly and bluntly 
apiculate, 2-2J lin. long, pale green with darker tips, quite glabrous,. 
Glumes thinly membranous, finely nerved ; lower ovate-lanceolate, 
3-nerved, middle-nerve raised towards the tip into a more or less 
bluntly ending keel ; upper glume as long as the spikelet, oblong, 
5-nerved, shortly keeled at the tip, the keel produced into a small short 
blunt appendage. Lower floret $ : valve very like the upper glume ; 
valvule almost as long as the valve, narrowly oblong, minutely 
truncate, keels scaberulous, flaps reversedly ciliate upwards ; anthers 
up to 1J lin. long. Upper floret oblong, bluntly apiculate, 
2-2J lin. long, whitish, smooth ; valve and valvule coriaceous, 
apiculus of valve roundish, very short, of valvule minutely and 
bluntly 2-toothed and slightly recurved. — Panicnm zizanioides, 
