Ovule of Bowenia spectabilis. 631 
have yet unthickened walls. They extend from the base of the ovule up 
into the micropylar region (Text-fig. 4). There is a definite and regular 
epidermis of small rectangular cells limiting the outer fleshy layer in which 
tannin sacs and mucilage ducts are beginning to appear. The inner fleshy 
layer is composed of rectangular parenchymatous cells which are indis- 
tinguishable from the adjoining cells of the nucellus. 
The Vascular Supply of the Ovule. 
In an ovule of this age it is easy to trace the vascular supply. Longi- 
tudinal and transverse sections of the ovule on the sporophyll can be 
cut before the sclerization of the stone layer. The bundles are, however, 
not fully developed, and the detailed description of them will be given later 
in connexion with the oldest ovule. Two series of vascular bundles are 
present in the ovule. The outer series consists of from 7 to 9 bundles which 
extend from the base into the micropylar region and only rarely branch. 
The inner series consists of 12-14 bundles at the base of the ovules. They 
branch frequently on their way up the ovule and number about 40 at their 
termination, which is usually just below the point at which nucellus and 
integument become free (Text-fig. 6). These bundles lie apparently on the 
border line between nucellus and integument. In some cases, however, 
which will be described later, there is reason to think that this inner vascular 
supply is nucellar. The whole of this vascular system is supplied by 
branches from one of the foliar bundles of the sporophyll (Text-fig. 7). 
The bundles of the sporophyll which serve the sporangia are markedly 
large, with a few elements of centripetal xylem ; cf. Worsdell. 1 The position 
and branching of the bundles can be made out by comparing Text-fig. 7 
and the series 8-12. In the stalk of the sporophyll the foliar bundle A 
divided into two branches, a and b — the former being the outermost. The 
branch a divides into a 1 and a 2 (dotted line) long before reaching the ovule, 
and these two branches serve mainly the part of the ovule nearest to the 
sporophyll. One branch supplies the anterior and the other the posterior 
region of this part, and each sends branches to both inner and outer series. 
The branch b , after dividing from a, , runs down for some distance in the 
sporophyll before turning in the direction of the ovule. It then forks and 
one branch,/# 1 , remains in the sporophyll, while b turns towards the base of 
the ovule. Before actually entering the ovule it gives off a second foliar 
branch,/# 2 . The branch # supplies the part of the ovule distal to the stalk 
of the sporophyll, and sends branches to both the inner and outer series. 
(#) Old Pollinated Ovules. 
The last of the normal ovules investigated were much larger than those 
previously described, and were in addition pollinated. The material con- 
1 Worsdell : Vascular Structure of Sporophylls of Cycadaceae. Ann. of Bot., vol. xii, 1898, 
