the Inflorescences and Flowers of Ephedra . 
977 
whole against it, and supports the view that the male flower represents an 
axillary strobilus. 
Attempts have been made by various authors 1 to show that the cover- 
ings of the ovules represent fused bracts, and that the female flower is 
consequently an axillary bud bearing one or two whorls of bracts and 
terminating in an ovule. Some have also tried to prove that the ovule 
is not the termination of the axis of this bud, but is borne on one of the 
surrounding bracts, which represents a carpel. 
Strasburger, in 1872, put forward the view that the outer covering 
in Ephedra and W elwitschia is the equivalent of a pair of leaves arranged, 
like the first leaves of an axillary shoot, transversely to the subtending bract. 
Jaccard also held the same view. According to it (Plan I, Text-fig. xxi) 
each half of the nut represents a leaf with a single median bundle instead of 
the pair of bundles formed in the normal vegetative leaf. But this sugges- 
tion is rendered unlikely by the 
V 
Text-fig. xxi. Plans of the ovule oiE.distachya. 
1. According to the view of Strasburger (first pair of 
leaves). 11. According to the view of Van Tieghem 
(second pair of leaves). III. According to the view of 
Lignier (whorl of three leaves). 
fact that there is often a third 
bundle, situated in a position 
which would correspond to the 
fused margins of the leaves. 
Strasburger changed his opinion 
in 1879 an d came to regard both 
coverings of the ovule as integu- 
ments. 
Van Tieghem regarded the 
outer covering as composed of 
two leaves, corresponding in posi- 
tion to the second pair of leaves 
of an axillary bud, in the same plane as the subtending bract ; the 
flattened surface of the nut with its two angles representing one leaf, 
traversed by two vascular bundles, the rounded, sometimes angled, outer 
portion representing the more or less abortive second leaf, sometimes 
supplied with a single vascular bundle. He regarded the ovule as borne 
on the inner leaf of the pair, a suggestion for which there is no evidence. 
Lignier attempts to overcome the difficulties involved in demonstrating 
that the outer covering of the ovule represents a pair of leaves by the 
suggestion that it represents three leaves, the three vascular bundles 
belonging each to one of the three leaves ; the female flower would thus 
become trimerous, the outer of the three leaves being more or less abortive. 
The inner covering he also regards as representing a whorl of three bracts, 
forming a tricarpellary ovary, the inner bract being the most developed, the 
two outer more or less abortive. There is no evidence to support the latter 
suggestion, and trimery is very infrequent in Ephedra. His attempts to 
1 Strasburger, 1872 ; Van Tieghem, 1869 ; Jaccard, 1894; Lignier, 1901 ; Arber and Parkin, 1908. 
