115 
If the omission of the described tomentum be due to inadver- 
tence there is no sixth form in the group; if the figure represent 
an actual specimen there is a sixth form. 
The treatment accorded to these six forms has varied from time 
to time. In 1786 Lamarck based upon the first form his descrip- 
the specimen he had described, while he did so endorse the speci- 
men which he cited. 
Vahl, who realised the difficulty thus created, drafted a new 
description of Croton senegalense based on the plant cited by 
Lamarck; this description Geiseler published in 1807. The pre- 
paration of a new description suggests that Vahl regarded the 
first form as specifically distinct from the second, though he did 
express that view or authorise Geiseler to do so on his behalf. 
A. Jussieu, however, in 1824 definitely decided that the first 
and second forms are specifically distinct; they constitute the two 
Senegal species of his summary. Later Desvaux, wh had ex- 
amined the same specimens, concluded that they only differ as 
two varieties of one species. : 
Ehrenberg, when he collected his specimens of the third form 
conclaided that it represented a distinct species which he issued, 
but did not describe, as Croton macrocalyz. 
of Croton macrocalyx. Visiani’s type cannot e 
that while it is probable that his plant, like that of Ehrenberg, 
belonged to the third form, the possibility that it may have 
belonged to the fourth cannot be wholly excluded. The fact that 
he intended the figure accompanying his description to represent 
the tomentose plant which he described, renders it almost certain 
that the absence from his illustration of any tomentum is merely 
due to some inadvertence on the part of the artist who prepared 
distinct iety of that species. " 
“a 860, Baillon, dealing then on iar _ first ma = 
the view he . Jussieu, and re- 
second forms, reverted to the vi ees 
first, with floccose tomentum he united with C. plicata. 
In 1862, * Schweinfurth, dealing eos the a —— 
I in Nubia, recognise 
third form collected by Hartmann in i ee 
. Brocchi. Vis. e Schweinfurth did not state, he seem 
$i: ply Soy his partial repetition of Visiani’s original figure ees 
E 
