the Inflorescences and Flowers of Ephedra . 981 
half of the antherophore with its paired bilocular synangia resembling far 
more closely one element of the disc of a Williamsonia than the micro- 
sporophyll of W elwitschia with its trilocular stalked synangium. 
The ovules of Ephedra and W elwitschia being in similar compressed 
positions differ in some respects from the freely projecting ovule of Gnetum , 
but in other ways they show remarkable similarity. They all have an inner 
thin membranous covering, fused with the nucellus below, free above, and 
prolonged into a narrow tube, lined in Ephedra, W elwitschia, and some 
species of Gnetum by a thick cuticle. The inner ring of vascular bundles, 
which in Gnetum is prolonged into the free part of this inner integument, in 
W elwitschia terminates at the level at which it becomes free from the 
nucellus, and in Ephedra at a still lower level. 
They all also have a thick outer covering. In Ephedra it is angled, 
and in Welwitschia it has two well developed wings ; in Gnetum it is smooth. 
The stony layer of this outer covering is always strongly developed at 
points corresponding to the external angles, and even in the smooth seed of 
Gnetum it is angled. 
Ephedra and Gnetum both have pollen-chambers, one of the signs of 
their greater primitiveness than Welwitschia , but even in Welwitschia there 
is some disorganization at the apex of the nucellus . 1 
The above evidence as to the reduced nature of Ephedra and its closer 
relationship to W elwitschia cannot be taken as indicating that it is reduced 
from W elwitschia. Its gymnospermous gametophyte and its well-developed 
pollen-chamber prohibit such a conclusion. But Ephedra and W elwitschia 
together appear to have retained in common numerous points which 
separate them off from Gnetum with its many singular characteristics . 2 Both 
genera show many signs of reduction, and W elwitschia has also, while 
retaining a less reduced strobilus than Ephedra and more primitive male 
flowers, undergone many remarkable vegetative modifications and a special 
elaboration of its ovules in the great growth of the nucellar apex correlated 
with its peculiar methods of fertilization. 
V. Summary. 
1. The vascular system of the inflorescences and flowers of various 
species of Ephedra is described. It is found that the method of supply of 
the axillary flower buds is similar in essentials to that of the vegetative buds 
in the axils of the ordinary leaves. Each vegetative bud and each flower 
receives three bundles : a median abaxial bundle (afterwards branching into 
two in the vegetative bud), intimately connected with the bundles of the 
subtending leaf, and two adaxial bundles which originate partly or entirely 
from the adjoining bundles of the main stem. 
1 Pearson, 1906, Fig. 28, PI. XIX, pp. 289-90. 
2 See also Pearson, 1912, p. 614; the male gametophyte, on the contrary, is most closely 
comparable in Gnetum and Welwitschia ; l.c. p. 618. 
