512 © DR. W. R. M^NAB ON WELWITSCHIA. 
Fig. 14. Fourth stage: b. base; o. p. outer parts of perianth (carpels) ; o. i. ovular integument ; n. naked 
nucleus. x 70 diameters. 
Fig. 15. Flower same age as fig. 14: seen from above, and slightly to one side; the ovular integument, 
o. i., seen as a ring round the nucleus, 2.; o. p. outer part of perianth (carpels), like two 
shoulders. x 70 diameters. 
Fig. 16. Fifth stage: letters as above. x 70 diameters. 
Fig. 17. Sixth stage: letters as above. The perianth (carpels) and ovular integument have risen above the 
nucleus. Two fibro-vascular bundles seen entering the flower at the base. x 70 diameters. 
Fig. 18. Seventh stage: letters as above. Embryo-sac represented. x 70 diameters. 
Fig. 19. Eighth stage: letters as above. Embryo-sac further developed, and perianth seen rising far 
above the nucleus. x 70 diameters. 
Dublin, Oct. 5, 1872. 
Since my paper was written and placed in Dr. Hooker's hands a very important 
memoir by Strasburger* has been published. In it he describes the development of 
Welwitschia flowers ; and we agree in all the more important points. There are, however, 
two differences which I must especially allude to. In the first place, Strasburger con- 
siders the two outer leaves of the female flower to be carpels, while I have described 
them as being part of the perianth. Strasburger in coming to this conclusion relies 
chiefly on analogy with Ephedra. Ihave not had an opportunity of examining Ephedra ; 
but if I may be permitted to give an opinion based on the study of Strasburger's figures 
and description, I would at once accept his view, and consider the female flower to consist 
of two lateral carpellary leaves and an axial nucleus with one integument. The only 
way to come to a definite conclusion on the subject is by the comparison of the flower of 
Welwitschia with those of Ephedra and Gnetum; and until I can examine them for 
myself I shall adhere to Strasburger's interpretation. 
In the consideration of the male flower, the main point on which we differ is in the 
development of the stamens. Strasburger considers them to form two whorls :—an outer, 
consisting of two stamens, lateral; and an inner whorl of four stamens, anterior and 
posterior. Theinner stamens are developed later and below the other two. My own pre- 
parations, which I have reexamined, do not bear out this view; and I think that in this 
point Strasburger has fallen into an error. If Strasburger's view is correct, the carpels 
are superposed to the inner whorl of stamens, while my view does not involve any such 
anomaly. | 
* Die Coniferen und Gnetaceen. 
