Ixxx The Transactions of the South African Philosophical Society 
Somewhat similar is the process of dissemination effected by a species 
of Stachys. The whorls of the flowers are arranged in a large, repeatedly 
dichotomous cyme. When the fruitlets ripen, the plant dies and breaks 
off above the ground. As it is very rigid, and of a nearly spherical out- 
line, it becomes an easy prey to the winds, and moves about until 
caught by a bush. In some parts of Griqualand West I saw numerous 
bushes that had put a stop to the progress of such a wandering plant. 
The second agent mentioned as assisting in the distribution of seed 
is water. In many cases it transports seeds that do not possess any 
special adaptation for such a mode of travel. The seeds are blown into 
the water, and if not compelled to remain in it too long, they will not 
suffer, but germinate at their landing-place. We have excellent 
illustrations of the results of such transport on the shallow banks of 
our periodically overflowing rivers, where often a plant suddenly 
appears in thousands that did not occur in the neighbourhood before. 
It is in this way that the Mexican poppy (Argemone Mexicana) often 
suddenly occupies a whole valley. 
A curious adaptation to these periodically occurring floods is shown 
by our common wild-melon (Citrullus vulgaris). Its fruits are per- 
fectly spherical, with a smooth, hard rind. A rush of water easily 
carries them over the plains of the interior, and I have seen hundreds, 
nay thousands of them, in the ditches along the railway line, where 
they had been swept in by the water and caught as in a trap. 
Quite different are the adaptations of the few water-plants which we 
possess. The seeds of the water-lily (Nymphea stellata) are provided 
with a black shining skin ; they are pretty hard, and yet they float on 
the water. There is a little cavity inside, filled with air, and conse- 
quently the seeds can be carried away, not only by a current of water, 
but also by the wind acting on the surface of the water. Somewhat 
similar is the adaptation of Aponogeton distachyon (‘water uintjes’), 
where the seeds are enclosed in a membranous capsule. The ripe 
capsules suddenly burst open and scatter the seeds over the surface of 
the water, where they float about on account of an oily outer skin, 
which surrounds the hard kernel like a loose little bag. The seed 
germinates while floating on the surface, and gradually forms the bulb. 
When this becomes heavy enough it sinks, and the plant fixes itself 
permanently. Slightly different is the process on Limnanthemum Thun- 
bergit, which forms air cavities in the capsule, which floats about on the 
water until it decays and liberates the seeds. 
The animals assist in two ways in the dissemination of seeds ; they 
carry them on their body, or swallow and deposit them afterwards. 
The adaptation for the first mode consists in hooks and spines, or in 
sticky materials, The achenes of Gewm are crowned by the hooked 
