122 Sahni. — On Certain Archaic Features in the Seed of Taxus 
discovered by him in New Caledonia. So far as the female organs are 
concerned, this plant might at first be taken for a large-sized species of 
Taxtis, the ovule being terminal on a bracteate axillary shoot, and the seed 
having a well-developed but free cup-shaped aril ; but a noteworthy 
difference is that there is a distinct ‘ internal 5 (nucellar) vascular system. 
A fact of further significance from our point of view is that the nucellar 
strands branch off from the main bundles at points roughly corresponding 
to those in Taxus , which are here also marked by slightly thickened knee- 
like bends. 
Attention may be drawn to the close proximity of the nucellus to the 
thickened knee-like bends in the strands of Taxus (Fig. 2). This part of 
the vascular supply is in fact nearer to the nucellus than is any other part. 
Fig. 6 from a transverse section at the level * * in Fig. 2 is given to 
show the striking similarity to Sprecher’s figure of Ginkgo ( 1907 , p. 134, 
Fig. 143) ; the broken line shows the region along which, at a higher level, 
the aril separates off as a ring. The vascular bundles of the bracts are very 
close to the adaxial surface : in the inner pair of bracts they are extinct at 
this level, their positions being marked by crosses. 
Theoretical. 
In 1903 Professor Oliver, in his well-known paper on { The Ovules of 
the Older Gymnosperms ’, showed how a seed like that of Torreya may 
be derived from a type such as the Palaeozoic Cavdiocarpus , with a free 
nucellus and a centralized main vascular supply at the base, entering the 
seed-cavity through a single median foramen in the stone. He postulated 
alongitudi nal splitting of the main supply of the ancestral seed-type into 
the two strands which now pass into the seed-cavity through two foramina 
lying in the principal plane. At the same time it is supposed that during 
the ancestral history of Torreya the base of the seed underwent a marked 
transverse expansion, 1 with the result that these two foramina, while retain- 
ing their position in the principal plane, gradually receded from each other ; 
and through the widening base of the seed the nucellus and megaspore 
bulged downwards into the apex of the seminiferous axis. This phylo- 
genetically younger portion of the seed, conveniently termed by Professor 
Oliver the hyposperm, is in Torreya so large in proportion to the 
archisperm (defining the original limits of the seed) that the ‘ ancestral 
chalaza ’ is actually nearer to the micropyle than to the lower end of the 
entire seed. 
1 This transverse expansion of the seed-base must be distinguished from the longitudinal 
extension postulated by Professor Oliver in deriving the seed of Cycas from the same ancestral type. 
Both processes result in the intercalation of a new region at the base, but the main supply splits 
longitudinally in the one case, while in the other case it remains unaffected. In this paper we shall 
concern ourselves only with the former case. 
