Rhodesian species of Fuirena , Hesperantha , and Justicia . 205 
limited branching system and, as far as early spring conditions go, no 
tendency to nodal rooting. Lobelia thermalis Thunb., a plant of very wide 
South African distribution, but in this case only found growing over rocky 
banks by a stream, was a very free surface-rooter, sending the rootlets down 
between the fissures of the rocks. On the veld the absence of surface 
moisture is no doubt a deterrent to this habit, and Justicia elegantida has 
had to adapt itself to surface-rooting by so organizing its vegetative growth 
that the energies of the plant can be directed towards the elaboration of a 
tuberous rhizome, and on this the starch-packed radical leaves are laid 
down. The plant is therefore doubly ensured against the long drought and 
the accompanying absence of moisture in the sandy surface of the soil. 
That the results are successful, is well shown in the wide distribution of the 
plant already referred to (p. 201), and it may be put down as one of the 
commonest Rhodesian types. 
Hesperantha matopensis calls for no further remark. The development 
of its corm-tunics is on lines common to tropical and South African bulbous 
plants, which, as Hackel has shown in the case of grasses, is characteristic 
of dry climates in general, and is correlated with the supreme necessity of 
ensuring a sufficient store of moisture round the roots and young shoots. 
Finally, my thanks are due to Dr. Rendle, of the British Museum, 
for kindly placing material at my disposal, and to Professor Farmer for his 
advice and criticism in the course of this work, 
Royal College of Science. 
May 2, 1907. 
EXPLANATION OF PLATES XI AND XII. 
Illustrating Miss L. S. Gibbs’ Paper on new Rhodesian Plants. 
0. ovule, r. raphe, v.b. vascular bundle, d.s. dead shoots, b.i. basal internode. sch. 
sclerotic tissue, e. endodermis. p, plexus of bundles, a.v.b. amphivasal vascular bundle, p.x.l. 
protoxylem lacuna, st. starch, t.s. tannin sac. l.t.b. leaf-trace bundle, c.b. cortical bundle. 
m.b. medullary bundle, b.h. base of hair. v.e. ventral epidermis, d.e. dorsal epidermis, a.c. air 
canals Lp . lignified parenchyma, w.s. water-sheath, m. mesophyll. p. palisade, st. stomata. 
PLATE XI. 
Fig. 1. A portion of a plant of Fuirena Oedipus showing the rhizome bearing old and young 
flowering and vegetative aerial stems, the basal internodes of which are swollen, forming starch 
storage-tissue ; the old stems to the right show reduction in size owing to the resorption of the reserve 
material. Reduced. 
Fig. 2. A flowering shoot detached from the rhizome. 
Fig. 3. A flowering spikelet detached from the inflorescence, x 16. 
Fig. 4. A flower in the axil of a bract. Mag. 
