354 Anatomie. — Biologie. 



and CalUtvis, Vent. (Proc, Linn. Soc. London. 122'^ Session, p. 50 — 

 51. 1909-1910.) 



In this paper evidence is brougth forward to shew: 1) that 

 Widdringtonia and Callitris do not conform to the '' Cupressineae''' 

 type , 2) that Widdringtonia cannot be merged in the genus Callitris, 

 but must rank as a distinct genus. Agnes Arber (Cambridge). 



Sykes, M. G., The Anatomy and Morphology of the Leaves 

 and Inflorescences of Welwitschia wirabilis. (Phil. Trans. Roy. 

 Soc. London, Ser. B. 201. p. 179—226. PI. 17-18. 1910.) 



This paper contains an extremely detailed account of the ana- 

 tomy of the leaves and inflorescences of Welwitschia niivabilis, 

 special stress being laid on the course of the vascular bundles in 

 the flower-axes and other parts. 



The author concludes that the male and female inflorescences, 

 cones, and flowers are homologous, She thinks it probable that 

 Welwitschia is not very closel}'^ allied to the other Gnetales. A com- 

 parison is made with the Cycads, the Bennettitales and the Angio- 

 sperms. It is pointed out that various characteristics of the vascular 

 System of Welwitschia connect it with the Cycads and the Medid- 

 loseae. In the characteristic dichasial branching of the inflorescences, 

 Welwitschia resembles WilUämsonia angustifolia. 



Agnes Arber (Cambridge). 



Sykes, M. G., The Anatomy of Welwitschia niirahilis Hook, f., 

 in the Seedling and Adult States. (Trans. Linn. Soc. London. 

 2. ser. Bot. VII. 15. p. 327—354. PI. 34-35. 5 Textfig.) 



The author has been enabled to add considerabl}'' to our know- 

 ledge of the anatomy of Welwitschia, through the examination of 

 material coUected b}^ the recent Percy Sladen Memorial Expedi- 

 tion to West Africa. 



One of the most remarkable features of the anatomical structure 

 of Welwitschia is the very small amount of primary vascular tissue. 

 The primar}'^ xylem is confined to the poles of the root, and the 

 four hypocotyledonary bundles developed from them, which supply 

 the cot3^1edons. Centripetal xjiem is developed in connection with 

 the four bundles in the bases of the cot3icdons. 



The four concentric groups of vascular tissue in the adult h}^- 

 pocotjd are compared by the author with the central steles of the 

 Medulloseae. 



All the main essentials of seedling structure are preserved in 

 the adult Welwitschia, and thus the comparison with the seedlings 

 of other plants is of special interest. The transition from stem to 

 root structure is found to take place in a manner closely resembling 

 that of Araucaria. The author concludes however that the resem- 

 blance is dependent on habit and not on relationship. 



Agnes Arber (Cambridge). 



Erikson, J., Bilder ur naturens tre riken. Läsebok i bio- 

 log i. H. 10. Blad ur jordens historia. [Blätter aus der 

 Erdgeschichte]. (272 pp. 127 Textfig. Lund, C. W. K. Gleerup. 

 1910.) 



Das vorliegende Hefi, mit dem das biologische Lesebuch abge- 



