GERMINATION AND HISTOLOGY OF WELWITSCHIA MIRABILIS, 29 
epidermis ceases, that is, immediately below the feeder. 
This state of things may be compared with that in the 
seedling of the Abietinez ;! in which case, however, a bundle 
sheath may be found surrounding the bundles. In the 
structure of the root itself will be seen a resemblance to that 
of those Gymnosperms which have a di-arch bundle system. 
The relation of the bundle system of the root of the young 
seedling to that of the older root remains still to be dis- 
covered. 
With regard to the plumule, it will be seen that the 
development of the two plumular leaves, decussating with 
the cotyledons, is a fact which is in complete accordance with 
what takes place in a number of conifere and guetacee (e. g. 
Thuja, Cupressus,” Cephalotaxus). Coupling the presence of 
the plumular leaves with the remnants of the leaves found 
in the plants preserved in the Kew collections, we are led to 
relinquish the older, and conferredly provisional view, that 
the whole plant of Welwitschia is a seedling arrested in its 
embryonic form. We now regard it as extremely probable 
(though not directly proved as yet) that the cotyledons of 
Welwitschia wither, while the two first plumular leaves 
remain persistent, and are the only two leaves developed 
from the plumule. The further history of the latter, and the 
morphological value of the structures which appear between 
the plumular leaves, I have not yet been able to determine. 
It will be noticed that there are still large gaps in our 
knowledge of the development of Welwitschia, while several 
morphological and histological questions of great interest 
remain unanswered. ‘The study of some of these problems 
I hope to be able to undertake later, with the help of fresh 
materials. 
_In conclusion, IT must acknowledge my thanks to the 
Director of the Royal Gardens at Kew, and to Mr. W. 
Thiselton Dyer, for the supply of materials, and use of the 
Jodrell Laboratory attached to the Gardens, as well as for 
the interest they have taken in my work, and for suggestions 
which they have made. 
Postscript.—Since the above was put into print, there has 
appeared in the ‘ Gardeners’ Chronicle’ (Nov., 1880) a 
communication from Chr. D. J. de Nautet Monteiro, who 
claims to have observed, in the germination of Welwitschia, 
a process differing from that described by me in ‘ Nature’ 
(October, 1880). He compares the case of Welwitschia 
with that of Commeleyna celestis. 
1 Of. De Bary, ‘ Vergl. Anat.’ 
2 *Coniferen and Gnet.,’ p. 322. 
