398 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



Sykes, M. G. (Cont.) 



1910b. The anatomy and morphology of the leaves and inflorescences of Welwitschia 

 mirabilis. Philos. Trans. Roy. Soc. London, B 201:179-226. 



SZAFEE, W. 



1949. Studies on the genus Tsuga Carr. in the Tertiary of Europe. Bull. Acad. 



Polon. Sci. et Lettr., CI. sci. math, et natur., ser. B, 1:23-51. 



Takhtajan, a. L. 



1950. Phylogenetic principles of the system of higher plants. Bot. Journ. Akad. Nauk 



SSSR, 35:113-139. (See Bot. Rev. [1953], 19:1-45.) 



Tammes, p. M. L. 



1930. On the Origin of Number and Arrangement of the Places of Exit on the Sur- 

 face of Pollen-Grains. Proefschrift, Univ. Groningen. 84 pp. Amsterdam: 

 J. H. de Bussy. 



Tansley, a. G. 



1908. Lectures on the evolution of the Filicinean vascular system. X. A comparison 

 of the vascular system of the ferns with that of other phyla of vascular 

 plants. New Phytol., 7:29-40. 



Thibout, E. 



1896. Recherches sur I'appareil male des gymnospermes. (These.) Fac. Sci. Univ. 

 Lille. 265 pp. Lille: L. Daniel. 



Thiergart, F. 



1949. Die Sciadopityszone und der Sciadopitys-Vorstoss in der niederrheinischen 

 Braunkohle. Braunkohle, Warme und Energie, pp. 153-156. 



Thoday, M. G., and E. M. Beeridge 



1912. The anatomy and morphology of the inflorescences and flowei's of Ephedra. 



Ann. Bot, 26:953-985. 



Thomas, H. H. 



1915. On Williamsoniella, a new type of Bennettitalean flower. Philos. Trans. Roy. 

 Soc. London, B 207:113-148. 



1925. The Caytoniales, a new group of angiospermous plants from the Jurassic rocks 

 of Yorkshire. Philos. Trans. Roy. Soc. London, B 213:299-363. 



1930. Further observations on the cuticle structure of Mesozoic Cycadean fronds. 

 Journ. Linn. Soc. London, Bot., 48:389-415. 



1933. On some pteridospermous plants from the Mesozoic rocks of South Africa. 



Philos. Trans. Roy. Soc. London, B 222:193-265. 

 1938. Pteridosperm evolution and the Angiospermae. Compt. Rend. 2eme Congr. 



Stratigr. Carbon. (Heerlen, 1935), pp. 1311-1321. 



Thomas, H. H., and N. Bancroft 



1913. On the cuticles of some recent and fossil Cycadean fronds. Trans. Linn. Soc. 



London, ser. 2, 8:155-204. 



Thompson, W. P. 



1910. The origin of ray tracheids in the Coniferae. Bot. Gaz., 50:101-116. 



1912. The anatomy and relationships of the Gnetales. I. The genus Ephedra. Ann. 



Bot, 26:1077-1104. 

 1918. Independent evolution of vessels in Gnetales and angiosperms. Bot. Gaz., 



65:83-90. 



