Rhodesian species of Fuirena , Hesperantha , and Justicia. 189 
Fuirena Oedipus C. B. Clarke. 
The aerial shoots of this species are about 20-40 cm. high (PI. XI, Fig. 1), 
and these arise at more or less regular intervals on the horizontal rhizome. 
The stem is four-angled, but the basal node of each aerial shoot is modified 
in the form of a round sessile pseudo-bulb with contracted base. These 
swollen internodes when collected were white and gleaming with a smooth 
surface, and are very apparent as they burst through the brown mem- 
branous scale-leaf of the node. The basal nodes are most developed in the 
flowering shoots of the current year (Fig. 2, b.i.) where they are globose in 
shape. In the vegetative shoots they are more elongated (Fig. 1) ; while in 
the dead shoots of the previous year, having given up all their reserve food 
material, they have shrunk both to the quadrangular shape and to the usual 
proportion of the stem (Fig. 1, d.s.). The plant was found at the Victoria 
Falls in September, growing in what, in a previous paper 1 , is described as 
the bog edge of the so-called Rain Forest. This bog edge consists of a 
zone of hygrophilous plants, varying in width and plant association, both 
apparently being determined by the intensity of the spray-fall from the 
cataract on the opposite side, during and after the rainy season, when the 
Zambesi is in flood. The river then falls in one sheet of water over its 
whole width, and the spray, which has been measured by theodolite to 
reach the height of 3,000 feet, is continuous and may be described as per- 
petual rain. When this plant was in flower, the river was almost at its 
lowest, reduced to about four separate falls. It was found growing almost 
opposite to the Devils Cataract, where only grasses and sedges formed a 
tangled mass. The spray at that season falls intermittently as a fine mist, 
according to the direction of the prevailing breezes. The foliage was some- 
times dry, but generally a dew-like moisture rested on the leaves, notwith- 
standing the continuous sunshine above. 
As might be expected from such surroundings, the plant is very hygro- 
philous in habit, the upper leaves showing long and broad laminae, while 
the scale leaves of the lower stem-internodes, and of the rhizome, are quite 
membranous in texture and not persistent. These facts, considered with 
the histological examination, agree with the results of other workers on the 
Gramineae and Cyperaceae, where biological conditions in relation to habitat 
have been taken into account 2 . Unfortunately investigation was limited 
to the type specimen, which increased the usual difficulties in dealing with 
herbarium material. 
HISTOLOGY 
Rhizome. The rhizome is small, about 2 mm. in diameter throughout, 
with short internodes. It is covered with brown scale leaves, in the axils 
1 Gibbs, 1 . c. 
2 Spinner, L’anatomie foliaire des Carex suisses, 1903. 
