ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 399 



BOTANY. 



(Under the direction of A. B. Rendle, M.A., D.Sc, F.R.S., F.L.S.) 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Vegetative. 



Cuticle of Leaves in Conifers. — R. Florin {Arkiv. Bot. Stochholm, 

 1921, 16, 1-32, 1 pi., 9 figs.). The author has studied the structure of 

 the leaves in Tsuya, Sequoia, Taxodium, Saxegothsea, Podocarpus, 

 CephalotaxHs, Torreya aud Taxus in order to discover any features of 

 vsystematic importance. Three types of margin can be distinguished — 

 viz. (1) That most frequently seen in species of Podocarpus, Sequoia, 

 Torreya and Taxodium, where the margin is entire and with little 

 cutinization. (2) That found in Sequoia sempervirens and Tstiga 

 canadensis, where the marginal cells are papillose, sometimes protruding 

 like teeth, especially near the apex, and the outer cell-walls are strongly 

 cutinized. (3) That found in Saxeyothsea and Taxus, where the margin 

 is undulate and strongly cutinized. The first type is of no special 

 systematic importance. The second is specially characteristic of two 

 genera, and may prove to be of use in determining species, although it 

 will not be possible to lay much stress upon it when dealing with fossil 

 forms, since the relatively weak walls of the papillte render them very 

 liable to destruction. The third type will probably be of great use in 

 determining fossil species. The form, size and arrangement of the 

 marginal papillge, taken in conjunction with the strong cutinization of 

 the cuticle, will afford a ready means of identifying different species of 

 Saxeyothsea and Taxus. 



An investigation of the stomata proved of great interest. In most 

 of the species examined they were confined to the under surface of the 

 leaf, but in Sequoia yiyantea, Taxodium distichum, Podocarpus eJonyata, 

 etc., they were also present on the upper surface, but this fact has no 

 systematic significance. There was a great similarity in the number of 

 rows or bands, which were usually parallel, with varying distances 

 between the rows and between the individual stomata. In Sequoia 

 sempervirens and in Taxodium distichum the rows are indistinct, while 

 their position with respect to one another aud to the direction of the 

 light varies. In the former the majority of the stomata are lengthwise 

 and never transverse, while the reverse is the case in the latter. These 

 characters have no systematic value, since similar irregularities occur in 

 Podocarpus and Torreya. The epidermal cells surrounding the stomata 

 have no special interest ; those between them vary in both size and 

 form, except in Torreya, where tliey are unusually long. 



