499 
Evolution of the A ngiosperms. 
male flower, than as belonging to the ovulum ; but in Gnetum , where three 
envelopes exist, two of these may, with great probability, be regarded as 
coats of the nucleus.’ 
In regard to Welwitschia, Hooker 1 considered that a perianth is 
present in both the male and female fructifications. He also showed that 
the outer envelope in the former is absent in Ephedra o*, while the inner 
is identical in appearance and position in both genera. He further states 2 
that, in the female fructification, the perianth ‘corresponds to the outer 
Fig. 2. Diagrammatic relative plans of the Gnetalean strobili, as here interpreted. Each 
strobilus is subtended by a bract. I. Welivitschia& , possessing a biseriate perianth, microsporangia, 
and a megasporangium. The strobilus is essentially dimerous. II. The 9 strobili of Welwitschia , 
Gnetum , and Ephedra. The inner perianth whorl and the microsporangia are suppressed. III. 
Ephedra distachya, Linn. <j. The outer perianth whorl and the megasporangium are suppressed. 
IV. Gnetum <5, similar to III, but differing as regards the microsporangia. 
(lateral) leaflets of that of the hermaphrodite 5 flower, and also ' to the 
outer coriaceous covering of the ovule in Ephedra and in Gnetum * (Text- 
fig. 2). This conclusion offers a simple explanation of the whole difficulty, 
and it is one with which we find ourselves in agreement, believing as we 
do that Welwitschia affords the real clue to the correct interpretation of 
the homologies of the Gnetalean fructifications. 
As is well known, Strasburger , 3 in his attempts to interpret the female 
Gnetalean fructifications in terms of the Coniferous cone, has naturally seen 
1 Hooker (’63). 
2 Ibid., p. 27. 
Strasburger (’79), p. 120. 
