ZOOLOGY AND BOTANY, MICROSCOPY, ETC. L87 



r>. The Osmundacea? are, therefore, very properly placed in Jeffrey's 

 phylum Pteropsida, the members of which are primitively phyllosiphonic. 



Chromosomes in Osmunda.* — S. Yamanouchi has studied the 

 behaviour of chromosomes during both homotypic and heterotypic 

 mitoses in Osmunda cinnamomea. He finds that : — 1. The reticulum in 

 the young nucleus arises from the chromosomes of the previous division 

 by vacuolation, and consists chiefly of chromatin. 2. The chromatin 

 network during the resting stage shows no indication of a pairing of 

 knots or strands. 3. Individuality of the chromosomes is retained in 

 the vacuolate and reticulate form during the resting stage, although the 

 limits of individual chromosomes become hard to trace. 4. The pairing 

 of chromatin material, perhaps of maternal and paternal derivation, 

 ■appears only at the early prophase of heterotypic mitosis. The pairs 

 may come into the closest association during synapsis, but the duality is 

 maintained. As a consequence no actual fusion occurs. 5. There is no 

 splitting of chromosomes in the heterotypic mitosis ; each bivalent 

 chromosome is formed by the association of two independent chromo- 

 somes. The separation of the two gives an appearance of longitudinal 

 •division. 



Apospory and Apogamy in Trichomanes.t — P. Georgevitch pub- 

 lishes a preliminary note on apospory and apogamy in Tricfiomanes 

 Kaulfussii, supplementing some observations by F. 0. Bower. He 

 describes the filamentous prothallium, its gemmge and their further 

 development into gametophytes bearing antherida and rhizoids. The 

 transition from sporophyte to gametophyte is attended by no alteration 

 in the number of chromosomes. The number of chromosomes is about 

 eighty in both generations. As to the nucleoli, the number and appear- 

 ance were the same in both generations. It is impossible to draw a 

 sharp line of distinction between sporophyte and gametophyte. As in 

 other plants, npospory implies absence of the meiotic phase. 



Stegmata in the HymenophyllaceaB.J — M. Boubier describes the 

 nature of the " stegmates " {stegmata, Deckzellen) discovered by 

 Mettenius in 1864. They are cells of peculiar character found in the 

 petiole or stem of some of the Hymenophyllacese, where they are applied 

 to the outside of the fibrovascular bundles or to the stereids, and have 

 their walls unequally thickened. The original cell-wall applied to the 

 vessels is of pectose with a little cellulose ; its strong internal secondary 

 thickening is much lignified in some species, and mainly of pectose in 

 other species. The middle part of the cell is occupied by a large 

 crystalloid body which consists of a silicious capsule inclosing a mass of 

 pectose strongly impregnated with silex. The author describes the 

 reagents which he used for his microchemical examination. 



Strobilus of Selaginella.§ — G. Mitchell gives an account of the 

 morphology of the strobilus of Selaginella with a view to completing the 

 .series of papers published by R. J. Harvey-Gibson upon the anatomy of 



* Bot. Gaz., xlix. (1910) pp. 1-12 (pi.). 



t Ann. Bot., xxiv. (1910) pp. 233-4 (fig.). 



t Bull. Soc. Bot. Geneve, ser. 2, i. (1909) pp. 281-4 (figs.). 



§ Ann. Bot., xxiv. (1910) pp. 19-33 (2 pis.). 



O 2 



