732 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology'of Seed Plants. 



Cytology, 

 including- Cell Contents. 



Chlorophyll Bodies.* — J. d'Arbaumont has made an extensive in- 

 vestigation of the chlorophyll bodies found in the sterns and leaves of 

 the Angiosperms and Gymnosperms. The writer classifies the chloro- 

 phyll bodies in two sections : in the first all the bodies are monotypic 

 and confined to special cells, while those in the second section may be 

 either in special cells or in any cells of the assimiiatory tissues of the leaf 

 and stem. These latter bodies, though inferior to those of the first 

 section from a morphological point of view, are superior to them in 

 respect to their function in the reduction of C0 2 . In the final stages of 

 their development, both series may or may not manufacture starch, and 

 consequently the latter substance is not of such great importance in the 

 building up of plant-tissues as is usually supposed. 



Structure and Development. 

 Vegetative. 



Seedling Anatomy .t—T. G. Hill and E. de Frame have investigated 

 the anatomy of seedlings of the Ginkgoaceae and Cycadaceaa, and find 

 that there are usually two cotyledons, which are imbedded in the pro- 

 thallus throughout their existence. They are often unequal in size, 

 and there is a tendency to form lobes at the apex and a cotyledonary 

 tube at the base. In the Cycadacese the cotyledons may fuse ventrally. 

 The number of bundles in each cotyledon varies, and is rendered more 

 complicated by fusion and branching. Transition-phenomena take 

 place rapidly, arid vascular re-arrangements are made within the hypo- 

 cotyl. In the Cycads examined the cotyledonary bundles fuse with the 

 plumular traces, and ultimately form a central cylinder. The seed-leaf 

 bundles play a very unequal part in the production of root-structure. 

 After the first root-structure is laid down, the number of poles may 

 increase at lower levels, and in Ginkgo protoxylem groups may be added 

 subsequent to the attainment of root-structure. 



Seedlings of Conifers. J— T. G. Hill and E. de Fraine have inves- 

 tigated the seedling structure of Tsw/a, Abies, Picea, Cedrus, Pinus, 

 Larix, Psendolarix, and Araucaria, in order to show that polycotyledony 



* Ann. Sci. Nat. Bot., ix. (1909) pp. 197-229. 

 t Ann. Bot., xxiii. (1909) pp. 443-58 (1 pi.). 

 % Tom. cit., pp. 189-227 (1 pi.). 



