GERMINATION AND EMBRYOGENY OF GNETUM GNEMON. 281 



the apex of the suspensor, I have not seen any specimen of 

 this, excepting one doubtful case. This cell divides by 

 anticlinal^ walls, of which none appear to be exactly median 

 (tigs. 3 — T).- The peripheral cells of the group thus formed 

 cTiow laterally along the surface of the suspensor, and, 

 dividing further by anticlinal walls, form short embryonic 

 tubes, comparable to those of Welwitschia, though much 

 less developed than these (cf. Strasburger, ^ Angiosp. und 

 Gymnosp.,' p. 155). The whole embryo now presents the 

 appearance of a single layer of cells covering the apex of the 

 suspensor like a hood (fig. 5). A cell is next cut off from 

 the suspensor by a transverse wall (fig. 8). Then follows 

 longitudinal division of the cell thus formed, while in the 

 lateral parts of the peripheral layer cells now begin to divide 

 by periclinal as well as by anticlinal walls ; one cell at 

 the apex, how^ever, divides by walls perpendicular to the 

 outer surface of the embryo, and inclined to one another 

 (figs. 6 — 9). This cell appears to be wedge shaped ; in fact, we 

 have to deal with a growth with an apical cell such as has 

 been observed by Strasburger in the case of many embryos 

 among the Coniferte {' Conif. and Gnet.,' p. 302, &c.), and 

 in a rudimentary way occasionally in Ephedra (' Ang. and 

 Gymn.,' p. 154). By this mode of increase of the peripheral 

 tissue, and by divisions both longitudinal and transverse of 

 the central group of cells, a large embryonic body is formed, 

 in the apical part of which the tissues differentiate in a 

 manner similar to that well known in other members of the 

 group. Internally a root-apex is formed, while externally 

 there appears at the apex of the embryonic body two cotyle- 

 dons and a central apical cone (fig. 10) . A definite epidermis 

 covers the cotyledons and the hypocotyledonary stem, but, 

 as is the rule in the Gymnosperms, the root has no such 

 covering ; the same is the case with the conical apex of the 

 stem ; here the peripheral cells frequently divide by peri- 

 clinal walls, while the extreme apex is not uncommonly 

 occupied by a single large cell (fig. 13). For the sake of 

 comparison, longitudinal sections were also cut through the 

 apical cone of branches of an old plant growing in the Royal 

 Gardens at Kew ; though many preparations were made, 

 including also the axillary buds, no undoubted case of 

 division of a peripheral cell by a wall parallel to the surface 



' I use this term in the same sense as Sachs, ' Ueber die Anordnung, 

 &c.,' Wurzburg, 1877. 



- Compare the embryo of "Welwitschia, as described by Strasburger 

 (' Coaif. uud Guet.,' p. 314). There the first embryonic cell is divided 

 crosswise, and no apical cell is formed. 



