SYSTEMATIC BOTANY. 487 



monograph, which is composed from Hooker's herbarium (Loud. Journ. of 

 Bot., 1845, pp. 410-70). 



CONIFERS. Koch read a paper on the Diagnosis of the European Species 

 of Pine, before the Association of German Naturalists (Ratisbon Flora, ] 845, 

 pp. 673-83). The new genus, Micocachrys J. D. Hook. (Lond. Journ. of 

 Bot., 1845, p. 142), has been mentioned above. 



GNETACE^E. We are indebted to the investigations of C. A. Meyer for a 

 profound monograph of Ephedra, an extract from which, containing the 

 diagnoses of nineteen new species, has appeared during the past year (Bullet. 

 Petersb., v. 33-36). 



CYCADEJE. Link endeavours to show that the position of the Cycadese 

 beside the Coniferse is untenable, and that they are more nearly related to 

 the Palms (Ratisbou Flora, 1845, p. 289). Independently of the embryo, 

 Schleiden's observation of the cambial layer beneath the bark (Grundziige 

 der Bot., 2, Ausg. ii, p. 152), also completely opposes these views. Link con- 

 siders the leaves of the Cycadese, in accordance with Miquel's views, as axial 

 organs. Miquel has explained his views upon the flowers, and especially 

 the ovule and embryo of the Cycadea3, more clearly than in his monograph, 

 and has illustrated his investigations by plates (Ann. Sc. nat., iii, 3, pp. 193- 

 206, pi. 8-9). He raises several objections to the view that the unilocular 

 anthers are mere cells of anthers. They grow out like anthers, from the 

 spadix; like them are surrounded by a layer of spiral cells, open by a fissure; 

 are sometimes separated from each other by rows of hairs, and develope the 

 pollen in the same manner as the unilocular anthers of other plants ; but all 

 these conditions apply also to dimidiate anthers, as in Salvia, so that the cells 

 of the anthers of the Cycadese only differ from the latter in their greater 

 number. Although the development of the embryo of the Cycadea3 has not 

 yet been observed, nevertheless, from the comparison of the ovule with the 

 seeds, and from the development of the former in the unimpregnated state, 

 it appears certain that impregnation takes place according to the same law 

 as in the Conifers. But since the main principle of the natural system of 

 botany depends essentially upon the reproductive organs, we thus have a 

 well-defined and peculiar character of the Gymnosperms in opposition to all 

 other Phanerogamia, as also the Loranthaceee with naked seeds viz. that 

 the embryo is not developed immediately from the pollen-tube, but from the 

 terminal cell of a cellular cord, the funiculus (R. Br., embryo-blastanon 

 Hart., Miq.), which, after impregnation, proceeds from peculiar receptacles 

 of the embryonic vesicles (corpuscula R. Br.) into the endosperm. The 

 unimpregnated ovule of the Cycadese differs from that of the Coniferse in 

 the separation of several enveloping layers of cells, the innermost layer 

 of which contains spiral vessels, so that they appear to correspond rather 

 with the idea of an arillus than an integumentary system, as Miquel supposes 

 (stratum externosum carnosum, secundum ligneum, tertium = textm cellularis 



