ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 65 



forming the rod with its contained slime strings. In the transverse 

 plates the action has gone further, and a single large slime string is 

 developed within the callus rod. 



Seedlings of Gesneriaceae.* — K. Fritsch gives an account of the 

 structure and anatomy of the seedlings of a number of genera of this 

 family, including Streptocarpus, Ramondia, Achimeiies, and others. The 

 author has also made a comparative study of the seedling and the adult 

 plant. In a more general section of the book he gives a review of the 

 morphology of the genus Streptocarpus, and a comparison with other 

 members of the group to which it belongs. 



Fossil Sequoia.t — E. C. Jeffrey gives a description of the structure 

 ■of the wood of a fossil Sequoia from the Auriferous Miocene Gravels 

 ■of the Sierra Nevada mountains. While showing structural features 

 which unite it with the living Sequoias, it has others which suggest the 

 Abietineae, such as the paucity of resin-cells present only on the outer 

 face of the svftnmer wood, the highly developed medullary rays, and 

 the traumatic resin-canals running both in the horizontal and vertical 

 planes. The fragment is described as a new species, S. PenhaUoivii, 

 •apparently most nearly allied to S. gigantea, of which it has the 

 geographical distribution. 



Reproductive. 



Embryogeny of Ginkgo.! — H. L. Lyon gives an account of his 

 detailed study of the embryogeny of this isolated gymnospermous type, 

 The mass of tissue which fills the egg after free nuclear division is 

 termed the protocorm. The cells in the micropylar two-thirds of this 

 spherical structure divide little or not at all, but those at the antipodal 

 end form a small-celled meristem, which passes over directly into the 

 meristem of the blastema or metacormal bud. The blastema pushes 

 into the endosperm as a broad blunt cylinder, the protocormal tissue 

 being forced back through the neck of the archegonium. Two " growth- 

 foci," — stem and root — are organised very close together in the axis of 

 the metacormal bud, and later the primordia of the two cotyledons in 

 the marginal region of the broad apical meristem. Hence much of 

 the original protocormal tissue is not involved in the organisation of 

 the embryo, — this is described as a rudimentary suspensor. Usually 

 there are two cotyledons, but three were quite common. The author 

 ■also describes the anatomy of the embryo. 



Physiology. 

 Nutrition and Growth. 



Mycorhiza of Pines.§ — A. Moller has conducted a research on 

 seedling pines of one and two years' growth. The latter part of the 



* Die Keimpflanzeu der Gesneriaceen. By Dr. Karl Fritsch. 8vo, iv. and 

 188 pp., 38 figs, in text. Fischer, Jena. 



t Bot. Gazette, xxxviii. (1904) pp. 321-32 (2 pis.). 



J Minn. Bot. Studies, iii. (1904) pp. 275-90 ( 14 pis.). See also Bot. Gazette, 

 xxxviii. (1904) pp. 390-1. 



§ Zeitschr. Forst. Jagdw. xxxv. (1903) pp.257 and 321. See also Centralbl. 

 B»kt.. xi. (1903) pp. 348-50. 



Feb. loth, 1905 f 



