DESCRIPTIONS OF THE SPECIES 
295 
broken pieces forming adventitious buds and starting fresh 
plants. Fertile fronds erect, two-pinnate, with linear segments, 
the margin folded round over the scattered sori. 
C. thalictroides (Linn.). Brongn .Bull. Soc. Philom. 1821; Hk. and 
Bkr, Syn. Fit. 174; C. Chr. hid. 169. 
Acrostichum thalictroides. Linn. Sp. 2, 1070 (1753). 
Tropics and sub-tropics of America, Asia, Australia, Africa 
and Madagascar ; floating in quiet waters. 
Portuguese East Africa. — Movene, near Lourenzo Marques (T. R. 
Sim) ; also Magenja da Costa and Messengerie in Zambesia 
(T. R. Sim). 
Sub-Order V. Gleicheniaceae. 
Genus 46. Gleichenia Smith. 
Rhizomes widely creeping, slender. Fronds distant, dicho- 
tomous, or repeatedly dichotomous, the ultimate branches 
with pinnately arranged pinnules. Sori on the back of the 
pinnules, composed of few capsules, without indusium. Cap- 
sules sessile, with a very wide, complete ring, and opening 
vertically by the separation of two joints of the ring. 
These beautiful ferns are distinguished at a glance by 
the dichotomous branching of the fronds, which occurs in 
no other South African genus. In the centre of each fork 
is a bud, and sometimes the one at the first fork develops 
late in the season into a strong branch, also dichotomously 
branching, thus giving the frond a somewhat pinnate appear- 
ance. The Gleichenias are quite distinct in appearance, and 
equal in beauty most ferns, but, unfortunately, do not readily 
adapt themselves to cultivation, and are seldom seen away 
from their native habitats. They are distributed through 
most of the Southern Hemisphere. There are about 80 
species. 
Key to the species : 
§ Pinnules nearly as broad as long. Sorus at the apex of a veinlet 
(Eu-gleichenia.) 
177. G. polypodioides. 
