T hi sell on- Dyer. — Morphologic ci l Notes. 1 2 5 
plants have been placed water-worn pebbles of about the same size from 
Thames Valley gravel. The plants not merely simulate them in form, but 
a mottling of the surface also reproduces their weathering. Personally, 
without referring to the living plants, I am unable, in many cases, to be 
quite certain which is which. 
Th zMesembryanthemum had two problems to face:- — (i)how to minimize 
the loss of water by transpiration : this is achieved by assuming the 
spheroidal form with its minimum surface. But (2) as soon as it became 
a succulent blob it was exposed to the danger of being eaten, and it only 
escaped this by pretending to be an inedible pebble. 
There are some dozen species of Mesembryan themum which form the 
small group Sphaeroidea. In these the vegetative organs have undergone 
the extreme of reduction and consist in fact of nothing more than a pair of 
succulent leaves which unite at the top, leaving a mere slit for the extrusion 
of the flowers. The leaves are from time to time renewed and the old 
ones shrivel and form a sheathing base to the new pair. 
Mr. Pillans obtained the plants which he sent to Kew from the Laings- 
burg District, which is in the same region as Zandvalley, where Burchell 
found it. 
In the Gardeners’ Chronicle for April 7, T900 (p. 2 1 1) there is an illus- 
tration from a photograph by Mr. Karl Dinter of another species, M. truri- 
catellum , which also simulates ‘ the stones amidst which it grows,’ though 
I think not so perfectly as M. truncatum . Mr. Dinter, however, who found 
it at Windhoek, says from actual observation that it ‘ so closely resembles, 
when not in bloom, the form and colour of the pebbles among which it 
grows, that it can only be detected by an experienced eye ’ (1. c., p. 115 ). 
It is figured in the Botanical Magazine for 1874, t. 6077. 
Mesembryanthemum Bolusii. 
This case is even more remarkable than the last. The mimicry is 
with angular rock-fragments instead of water-worn pebbles. It was 
discovered some time previous to 1877 by Mr. H. Bolus, the well-known 
South African botanist, and named and described in his honour by 
Sir Joseph Hooker in the Botanical Magazine for 1882. It has been three 
times in cultivation at Kew. The first specimens appear to have been 
promptly stolen ; the second not to have survived ; for the third we were 
indebted to Mr. C. J. Howlett, Curator of the Botanic Garden, Graaf 
Reinet, an old Kew employe, who sent it to the Royal Botanic Gardens in 
1903. Sir Joseph Hooker describes technically the pair of leaves which 
practically compose the plant as ‘ trigonously hemispherical.’ They closely 
resemble angular stones, of which the weathering is imitated by the ‘dull 
grey-green surface, and the resemblance is enhanced by the minute pustular 
