310 
then are sown with the capim gordura (T'ristegia glutinosa*) a 
grass very much relished by cattle, which grows so dense and 
luxuriant that even the stubborn sape (i.e. Andropogon bicornis) 
must literally quit the field in this struggle for existence.”’ 
clear from these extracts that in Brazil at any rate, this grass 
shows extreme aggressive powers on soil which has been disturbed 
and deprived of its natural vegetation, and there is no apparent 
reason why it should not behave in tropical Africa in the same 
manner whenever it gets a chance to do so, although it may be 
powerless among a vegetation in a state of established equilibrium. 
In connection with the above Dr. Stapf considers the following 
remarks on two other species of Melinis worthy of notice. 
Melinis effusa, Stapf—This species is so far known only 
from Angola and the Lower Congo region, It was discovered by 
Welwitsch in “ sandy wooded places ” in Pungo Andongo and in 
‘poor soil in sunny places’ in Golungo Alto in 1857 and 1855 
respectively. Then in 1900 J. Gillet found it near Kisantu and 
R. P. Butaye in the neighbourhood of N’Lemfu, both localities 
in the Stanley Pool Division of the Belgian Congo, and according 
to Dawe it is common in the Portuguese Congo. Nothing is 
known about its ecology or economic value, but in general 
appearance it is so much like M. minutiflora that it might be 
expected to behave similarly. 
Melinis tenuinervis, Stapf.—Although this grass is not included 
under the general term Efwatakala as illustrated by Mr. Dawe’s 
specimens, it may yet be useful to call attention to it, as it has 
apparently been mistaken by various authors for M. minutiflora— 
myself described it originally as a variety under the name pilosay 
—and replaces that species over a very large area extending from 
Southern Angola through the Southern Congo (Katanga) and Rho- 
desia to Natal and Nyasaland, whilst it resembles it sufficiently 
to suggest similar properties although the hairiness and viscosity 
of the plant is much less pronounced than in the two Efwatakala 
grasses. At any rate it might be taken into consideration as a 
possible substitute of M. minutiflora in districts which are not 
suitable for that grass. Unfortunately nothing is known about 
the ecology of M. tenuinervis. 
The structure of the hairs has been worked out in the Jodrell 
Laboratory at Kew, by Mr. 8. Dickinson, of the Imperial College 
of i Selene with a view to ascertaining in what manner the oil was 
reted. He reports as follows :— 
“An examination by the naked eye shows the leaf sheaths 
enclosing the stem to be covered with hairs most of which, under 
a pocket lens, can be seen to have a drop of oi] at the apex. The 
hairs are most numerous on the leaf sheath, but they also occur 
on both sides of the lamina. On the young sheaths whilst they 
* A synonym of Melinis oot rt 
{ Flora Capensis, VII. p. 4 
