30 DR. J. D. HOOKER ON WELWITSCHIA. 
tend to show that it is compound. The ovule, on the other hand, up to this period of 
growth, shows no further traces of composition than the double vascular system which 
terminates at the base of its nucleus; it is organically absolutely terminal, being erect, 
central, and continuous with the axis of the perianth, without constriction, both in the 
male and female flowers: lower down, these two vascular cords are confluent with the 
two main vascular bundles of the perianth; and the cellular tissue which is contained 
between these cords is similarly continuous with that of the nucleus of the ovule. 
I believe that, in respect of this anomalous disposition of vascular cords at the base of 
the ovary, Welwitschia presents but a slight deviation from the arrangement which 
obtains in other Gnetacee, of which Ephedra has three corresponding bundles, and 
Gnetum many; but it presents a remarkable contrast to what occurs in Conifere, and, 
in connexion with the other peculiarities of the ovule, and with the relations of the 
flower to the scale, it renders it impossible to reduce the inflorescence of the three genera 
(Ephedra, Gnetum, and Welwitschia) to the same type with that of Conifers as generally 
understood. 
Assuming Brown's view of the ovule of Conifers, and mine of that of Gaetacec, to be 
correct, that each presents a nucleus with one or more integuments which are not of 
carpellary origin, we have, then, in biovulate Conifere two ovules lying on an open scale, 
regarded by most as carpellary, but by some as ramal, and this again subtended by 
another scale, which is regarded as bracteal. The obvious mode of harmonizing the 
relations of these organs is, to regard the ovuliferous scale of Conifere as not carpel- 
lary, but perigonial, or the perianth of Guetacee as carpellary. It would be out of 
place to discuss here the first proposition, because (though by no means proven) the 
balance of evidence is decidedly in favour of the carpellary nature of the ovuliferous 
scale, at least in the Adietinee; and the second proposition is entirely negatived by 
the structure of the hermaphrodite flower in Welwitschia. Then, again, the ovuli- 
ferous scale in Abietinee supports two ovules; and the fact that Braun and Caspary * 
have found it replaced by two leaves would indicate that, if carpellary, either the 
ovarium is here compound, or each bract supports two flowers, each flower being repre- 
sented by a uniovular carpel, and that, for comparison with Welwitschia, we must 
resort to the uniovulate Conifere, such as Araucaria, Dacrydium, Podocarpus, &c., the 
correspondence of whose scales with those of <Abietinea, &c., is not in all cases 
ascertained. 
There is nothing in the development of this ovule that favours the opposite theory, 
that the integument of the nucleus in gymnospermous plants is of carpellary origin, 
except the singular form and relative position of that organ in the hermaphrodite flower. 
In position, texture, structure, and development, it entirely resembles the coat imme- 
diately investing the nucleus in all other Gymnosperms; like these, and unlike carpel- 
lary organs, it is entirely devoid of vascular tissue in its substance, and of conducting 
* Caspary ** On the Morphology of the female Flower of the Abietinese ;" translated in Nat. Hist. Review, 1862, 
p. 19. Parlatore (Ann. Sc. Nat. sér. 4. xvi. p- 215) considers the scale to be a shortened branch, having its leaves 
or bracteoles more or less confluent together and with the bract and the pistil (ovule). 
