the Inflorescences and Flowers of Ephedra . 983 
together. Other species exhibit further stages in this reduction process, 
more and more synangia fusing together, often forming in the process 
trilocular or even quadrilocular synangia, until E. altissima is arrived at with 
only two bilocular synangia. The formation of trilocular synangia as 
a result of fusion affords a link with Welwitsckia, where terminal trilocular 
synangia are normally produced. In most species the synangia are nearly 
sessile, but in E. Torreyana and a few others they are borne on a stalk of 
some length, reminiscent again of the stalk freely projecting above the fused 
portion of the staminal whorl in Welwitsckia . 
7. From the evidence available it is concluded that the structures in the 
axils of the fertile bracts in the male cone are to be regarded as flowers, or 
little strobili, each consisting of one axis bearing four leaves. The first pair 
of leaves, which, except in E. fragilis , receive no vascular supply, are 
orientated like the second pair borne by a vegetative axillary bud, and the 
two flattened halves of the fertile organ thus appear to represent the third 
pair of leaves fused with one another back to back. In E. fragilis they 
exhibit circinnate vernation in the bud. 
8. This bipartite sporangiophore with its paired bilocular synangia is 
compared with the six-partite disc of sporophylls in Welwitsckia and with 
the multipartite disc in the Bennettitales. It is thought that we can trace 
the steps of a reduction series from the disc of Cycadeoidea with its bipinnate 
sporophylls, through such stages as Williamsonia whithiensis , in which the 
segments are small and simple, and each bears a row of paired bilocular 
synangia, the lower of which are abortive ; and the disc of El Consuelo in 
which the freely projecting portions of the disc are no longer flattened but 
bear stalked synangia; to Ephedra, where the disc is reduced to two segments, 
each bearing two pairs of bilocular synangia, and Welwitsckia , where it is 
composed of six segments, each with a stalked terminal trilocular synangium. 
From the reduction series in Ephedra itself it is seen how from the fusion of 
bilocular sporangia a single trilocular stalked synangia can be produced. 
9. Whether the female flower also in Ephedra and Welwitsckia is, like 
the male, morphologically a little strobilus and the equivalent of an axillary 
bud, it is not easy to decide, since it consists of an isolated ovule ; the more 
complicated relations occurring in Gnetum make the matter still more 
difficult. The male sporangiophores having been related with some show 
of probability to the disc of sporophylls in the Bennettitales, it seems 
justifiable, considering the many signs of reduction in the Gnetales, to suggest 
that the single ovule now developed at the apex of the axillary structure 
in the male and female flowers of Welwitsckia and in the female flower of 
Ephedra represents the many ovules and interseminal scales of such a flower 
as Cycadeoidea fused together. This is rendered the more possible by the 
discovery that fusion of ovules actually occurs in Ephedra , resulting in the 
production of a uniovulate from a biovulate cone. 
