448 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Mechanics of the Dehiscence of Anthers.* * * § — Herr C. Steinbrinck 
has investigated the cause of the dehiscence of ripe anthers, and agrees^ 
with previous observers in liis account of the structure of the anther- 
wall at the line or point where the dehiscence takes place. The wall 
consists of three layers of cells, the middle of which is provided with 
thickening-fibres. In his mechanical explanation of the rupture he 
agrees most nearly with Schrodt, ascribing the cause chiefly to changes 
which take place in the thin portions of the radial walls. 
Female Flower of Coniferse.j — M. M. Eadais has studied the develop^- 
ment and structure of the female flower in the various tribes of Conifers. 
It is only, he states, in the Taxoidese that the seed remains naked 
till maturity ; and in them it is protected by a very firm integument, 
and frequently by an aril as well. In the Pinoideae the ovule is naked 
only till the time of flowering ; from that time the scales of the cone 
» fiord it an even more complete protection than that possessed by many 
Angiosperms. The ovule, with its integument, takes over, in Coniferae, 
nearly all the functions which, in Angiosperms, belong to the flower. 
The author regards the Coniferae as Archegoniatae, in which the 
phenomena of impregnation have been modified in consequence of this 
process taking place outside the water. The megasporange (nucellus) 
is furthermore enclosed in an integument homologous to that of the 
ovule of Angiosperms. The antherozoid is replaced by a non-motile 
gamete ; and this is accompanied by a reduction in the size of the male 
prothallium, and in a modification in its form to facilitate the carriage 
of the male to the female gamete. The detention of the pollen-grain 
which, in Angiosperms, is effected by the stigma, is, in Conifers, brought 
about by the integument of the ovule. 
The term flower is used in a somewhat different sense, homologically, 
in Conifers to what it is in Angiosperms ; the ovule of the former 
corresponding to the pistil of the latter, i. e. to a female flower of the 
simplest kind. 
Phyllotaxis. f — M. C. De Candolle derives the following general 
conclusions from" a study of the various forms of phyllotaxis : — With 
radial shoots the phyllotaxis depends essentially on the elongation of 
these shoots by transverse growth ; the foliar protuberances must be 
considered as the effects of local accelerations of transverse growth. 
This accounts for the diminution of longitudinal growth at the growing 
point. During the development of each shoot the relation of growth in 
length to transverse growth usually increases at first and subsequently 
diminishes. It is this diminution which causes a crowded phyllotaxis, 
such as that of buds and of floral organs, near the extremity of shoots 
or of their ramifications. 
Anisophylly.§ — Prof. J. Wiesner describes several fresh examples 
of anisophylly in tropical plants, including a new form which he terms 
* Ber. Deutsch. Bot. Gesell., xiii. (1895) pp. 54-61 (5 figs.). Cf. this Journal, 
1885, pp. 91, 1032. 
t 4 La fleur femelle des Coniferes,’ Paris, 1894, 103 pp. and 27 figs. See Bot. 
Centralbl., lxi. (1895) p. 329. 
1 Arch. Sci. Phys. et Nat., xxxiii. (1895) pp. 121-47 (1 pi.). 
§ Ber. Deutsch. Bot. Gesell., xii. (1894) Gen.-Vers.-Heft, pp. 89-93. 
