Duthie. — Anatomy of Gnetnm africanum. 601 
vascular bundles, and also occur in the broader parts of old medullary rays. 
Branched acicular cells with lignified and finely striated walls occur in the 
pith and cortex of the nodes. Elongated fibres with enormously thickened 
cellulose walls are present in large numbers in the cortex. 
Latex vessels with cellulose walls and dense albuminous contents occur 
in pith and cortex, also in petiole and lamina of the foliage leaf. 
Cork formation is exceedingly irregular. The phellogen originates in 
circumscribed areas of the epidermis and spreads peripherally. It is not 
unusual to find periderm formation cutting deep into the cortex at certain 
points, and occasionally groups of fibres are completely isolated by cork 
cells. Division of the ground tissue cells within the sclerenchymatous zone 
was observed. 
The stem apex was found to possess a small-celled meristem. 
Four bundles pass into the base of each foliage leaf, the median leaf- 
traces being the first to leave the vascular ring. The bundles which supply 
the scale leaves subtending the lateral shoots branch on passing through the 
cortex, a number of the bundles passing into the axillary shoots. 
The reticulate venation is of the usual Dicotyledonous type. 
A single layer of short, palisade cells occurs below the upper epidermis. 
The spongy parenchyma consists of many-armed, loosely packed cells. 
Fibres and branched acicular cells are present in large numbers in the 
mesophyll of the leaf. 
The stomata are arranged irregularly oyer the under surface of the 
lamina with the exception of the veins and veinlets. They also occur on the 
upper surface over the midrib, and are about on a level with the surrounding 
epidermal cells. The outer wall of each guard cell is provided with a ligni- 
fied flap. The stomata of the young stems are sunken below the level 
of the epidermis. 
Literature cited. 1 
1 . Boodle, L. A., and Worsdell, W. C. : On the Comparative Anatomy of the Casuarineae, 
with Special Reference to the Gnetaceae and Cupuliferae. Ann. Bot., viii, 1894. 
2 . Bower, F. O. : The Germination and Embryology of Gnetum Gnemon. Quart. Jour. Micr. Sci., 
xxii, 1882. 
3 . de Bary, A. : Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns. 
English translation. 1884. 
4 . Dingler : fiber das Scheitelwachsthum des Gymnospermenstammes. Miinchen, 1882. 
5 . Griffiths, W. G. : Remarks on Gnetum. Linn. Trans., xxii, 1859. 
6. Hill, T. G., and de Fraine, E. : On the Seedling Structure of Gymnosperms. IV. Ann. 
Bot., xxiv, 1910. 
7 . Stapf, O. : Die Arten der Gattung Ephedra. 1889. 
8. Strasburger, E. : Die Coniferen und die Gnetaceen. 1872. 
9 . Welwitsch, F. : Sertum Angloense. Linn. Trans., 1869. 
1 In several cases the entire paper was not available and extracts only were seen. 
