l66 TlMEHRI. 
pronounced way by plants characteristic of that moun- 
tain, such as Marcetia taxifolia Tr. [No. 68], Cassia 
Roraima?, Bth. [No. 71], Dimorphandra macrostachya, 
Bth. [No. 39I, Meissneria microlicioides Ndn. [No. 174], 
Calea ternifolia, Oliver, N. sp. [No. 27]. To me the 
most interesting plant on this river was a very beau- 
tiful little slipper orchid (Sclenipedium Klotzschiamim,) 
Reich, fil. [No. 31], which grew in the moist gravel of 
the river bed, where the plants must frequently be 
under water. This plant we also found in great abund- 
ance on an island in the Cotinga river, another of the 
Roraima rivers, and on a small creek, called Aroie, a 
tributary of the Cotinga. Naturally the Arapoo river, 
as are its fellows flowing from Roraima, is an artery 
allowing of the dissemination of plants from that moun- 
tain. 
At last we reached the Kookenaam river at the village 
of Teroota — at the base, that is, oi Roraima. But even on, 
beyond the bed of this river, for some distance up the 
slope of the mountain, the tract of ordinary savannah 
vegetation still continues, its characteristic plants, how- 
ever, ever becoming more and more penetrated by 
plants belonging to the Roraima flora, till the very 
distinctly marked zone of strictly Roraima vegetation is 
reached. 
The course of the Kookenaam river, where it here 
flows through the tract of neutral vegetation — vegetation, 
that is, not yet deprived of ordinary savannah plants 
and not yet composed exclusively of Roraima plants — is, 
as was the course of the Arapoo river already described, 
— very well defined by the large number of Roraima 
plants clustering on its banks. Among these may be 
