975 
the Inflorescences and Flowers of Ephedra . 
Gnetales and Bennettitales are derived from the same stock, the leaf-like 
character of the disc of male organs in Ephedra and Welwitschia is of 
interest as tending to support this relationship. We now know, among the 
Bennettitales themselves, many examples of discs of male sporophylls much 
reduced from their original leafy and pinnate form. In IV. rajmahlensis } 
for example, the segments of the disc are few in number and no longer 
flattened, but consist of a branched axis-like structure, bearing each a row of 
bilocular synangia, seemingly very suggestive of the male organ in Ephedra, 
Wieland 2 also has lately drawn attention to the resemblance between the 
small male discs of Wielandiella , the reduced structure of which has 
recently been redescribed by Nathorst , 3 and the disc of six fused male 
sporophylls in Welwitschia. Such simple discs as those of Williamsonia 
whitbiensis 4 are perhaps even more suggestive of the staminate disc of 
Welwitschia. In this species there is a disc of fifteen simple leaf-like seg- 
ments, fused at the base, projecting freely above ; the free portion of each 
segment bears a row of paired bilocular synangia, while below the free portion 
this row is continued downwards by synangia which have become abortive. 
So that here reduction in the size of the segments and abortion of the 
lower synangia has already begun. Granted only the further continuation 
of reduction and abortion, the separate flattened segments of such a disc 
may easily be compared with one of the two flattened segments, fused 
below, free above, of the sporangiophore of such a species as Ephedra 
distachya, in which a row of only two pairs of bilocular synangia is borne 
by each half of the bipartite disc. Welzuitschia differs in that the six 
members of its disc, similarly fused below, are continued upwards, not as 
flattened segments bearing paired bilocular synangia, but as cylindrical 
axes each terminating in a single trilocular synangium. In Wieland’s 
staminate disc of El Consuelo/ in some respects less reduced than 
W. whitbiensis , the free portions of the disc are not flattened but cylin- 
drical, and bear paired lateral synangia on stalks, and we have already seen 
in Ephedra itself 6 how easily a stage with paired lateral synangia can 
undergo reduction by fusion and abortion of the synangia, in the process 
of fusion trilocular synangia being produced. All that is required to 
derive the male disc of Welwitschia from Williamsonian discs such as 
these is the abortion of the lower pairs of synangia, already begun in 
W. whitbiensis , and the fusion of the topmost pair to form a trilocular 
synangium, such as is produced by fusion in Ephedra. 
B. The Female Strobilus (cone). The restricted number of ovules in 
the female strobilus (cone) of Ephedra stands in marked contrast to the 
numerous ovules found in the strobili of the other Gnetales. In the groups 
of species in which the bracts are succulent the whole strobilus is very 
1 Wieland, 1911, p. 461. 2 1. c., p. 438. 3 Nathorst, 1910. 
* Nathorst, 1911, especially Fig. 3, p. 13. 5 Wieland, 1909, p. 433. 6 p. 971. 
