487 
Boivenia spectabilis , Hook. f. 
examined with a view of determining the development of the 
transfusion-tissue. But it is equally probable that a poor 
development of this tissue is characteristic of Bowenia , as it 
has been shown to be in the case of Stangeria 1 . Bowenia 
and Stangeria are alike in that the venation of the leaf 
consists of closely- arranged sub-parallel members of a dicho- 
tomously-branched system, by means of which the leaf is well 
supplied with conducting-tissue : and under these circum- 
stances it is reasonable to suppose that the specialization of 
transfusion-tissue is dess necessary than in cases in which 
the leaf is not so well provided with ordinary conducting- 
tissue. 
Engler’s statement 2 that the anastomosis of the veins 
described by Schimper does not occur, is confirmed in the 
case of the leaves of the seedling-plant. 
The general structure of the lamina of the adult leaf has 
been fairly fully described by Nestler 3 . With a single, not 
unimportant, exception, this account is correct for the leaves 
of the seedling-plant. He states (p. 356) that the stomata of 
Bowenia differ from those of all other Cycads in that they are 
found upon the upper as well as the lower side of the leaf. 
Though many leaves were examined, not a single stoma was 
found upon the upper side of the leaf ; whilst stomata of the 
kind described by Nestler were very abundant on the lower 
side. In comparing these two accounts it should be borne in 
mind that our plants were grown under glass in the Tropical 
Pit, a condition which may have affected the development of 
the stomata. 
It was perhaps to be anticipated that an examination of 
young plants of Bowenia would disclose the existence of 
primarily concentric vascular bundles, the presence of which 
would lend support to the phylogenetic evidence supplied by 
the bipinnate leaf. However, no indication of the existence 
of such bundles in any part of the plant has been found in the 
1 Worsdell, loc. cit. , Trans. Linn. Soc. 2 Engler and Prantl, ii. i, p. 9. 
3 ‘Ein Beitrag zur Anatomie der C ycadeenfiedern,’ Pringsheim’s Jahrbiicher, 
Vol. xxvii, 1895, p. 356. 
L 1 
