Ixxvi The Transactions of the South African Philosophical Society 
named bergklapper (mountain rattle) accordingly. How easily plants 
are spread in this way over vast regions is well illustrated by our wild 
tobacco shrub (Nicotiana glauca), a citizen of South America. From 
Cape Point to the tropic of Capricorn, and even beyond it, I have seen 
this plant everywhere, few days of my travels having passed without 
my coming across some specimens of this intruder. 
The capsule very often acts as a catch for the wind, imparting a 
greater force to the seed when thrown out—e.g., the pods of Crotalaria, 
Podalyria, Lessertia, and other leguminous genera. As one of the most 
ingenious arrangements of this kind, Cysticapnos Africana may be men- 
tioned. The capsule is largely inflated ; the epicarp is a thin membrane, 
the mesocarp a delicate spongy tissue, and the endocarp forms a flat 
central receptacle. This central portion, which contains the black 
shining seeds, is suspended from the edges of the epicarp by means of 
thin threads. When the capsule opens, the endocarp remains attached 
to the stalk like the septum of the cruciferous fruit, and the two hollow 
valves, attached to the endocarp only by means of the threads, render 
this light structure so bulky that, although it weighs only one grain, 
its volume is a little more than 4 cubic inch, and its specific gravity 
consequently ‘004, or about 4, that of cork. 
The seeds of orchids and heaths, in themselves smaller than most of 
those just mentioned, are light and buoyant like the finest dust, for 
these tiny things consist of a thin seed-coat loosely surrounding an 
almost invisible kernel (see Figs. 1 and 2). But even knowing this, it 
is surprising that it takes 26,000 seeds of a large-flowered heath (Hrica 
coccinea), to make one gramme, or 1700 to the weight of one grain. 
Some seed-vessels are so light and papery that every gust of wind 
carries them along the ground, ¢.g., Cassia ardchoides, and others are so 
largely inflated that the effect is the same, ¢g., Aitonia Capensis, Cardio- 
spermum Halicacaba, Erythrophysa undulata, Melianthus major, Sutherlandia 
Jrutescens. In afew cases it is the inflated calyx that assists in the 
same way, ¢.9., Leoyena glabra and in Dombeya Natalensis the petals 
become enlarged and papery after the flowering season. 
The appendages adapted to the action of the wind are either wings 
or hairs or tails. The simplest case is represented by the flat seeds of 
Aloe, Morea, Watsonia, and many other genera of the orders Liliacez, 
Iridaceee, and Amaryllidacez. 
On other seeds the margin is extended into a membranous wing, ¢.9., 
many Iridacee and Caryophyllacese, Leucadendron adscendens and L. 
grandiflorum, Augea Capensis, Catophractes Alexandri, Montinia acris, 
Tecoma Capensis, Pteroxylon utile. This often becomes a one-sided wing, 
e.g., the Clanwilliam cedar (Callitris arborea); while in Anacampseros the 
seed is covered with numerous little wings. 
