46 BOTANICAL GAZETTE [yULY 
region contains a tangle of long, tortuous, and branching suspensors 
(figs. 6, 7), which are difficult to trace. During the formation of a 
suspensor by a fertilized egg, free nuclear division occurs, resulting 
in a few nuclei (four in fig. 7) distributed along the suspensor. Usually 
between these nuclei transverse walls are formed by the development 
of a cleavage plate from the wall of the suspensor. A cell at the 
tip of the suspensor is cut off in the same way, and contains one of 
the free nuclei, which becomes associated with numerous starch 
grains (jig. 7). 
In this terminal embryonal cell free nuclear division continues 
(figs. 8, 9, 10), accompanied by cleavage walls, until a multicellular 
embryo is formed. In figs. 9 and zo it will be observed that this 
cleavage apparently continues until uninucleate cells are produced; 
and in our material this stage is reached first by a group of cells on . 
one side of the embryo. It could not be determined whether this 
group holds any relation to a body region or not. 
It has been supposed that in the embryogeny of Gnetum the 
preliminary stage of free nuclear division, common to other gymno- 
sperms, had been eliminated; and that the first nuclear division was 
accompanied by wall formation, as in angiosperms. In Gnetwm 
Gnemon, however, free nuclear division not only characterizes the 
proembryo, but also the early stages of the embryo. The case may 
be compared to that of Ephedra,’ in which free nuclear division 
within the fertilized egg results in eight independent proembryonal 
cells, each of which continues free nuclear division and develops aS _— 
a suspensor, which by a cleavage wall cuts off the terminal embryonal . 
cell. In Gnetum the suspensor is formed by the fertilized egg instead 
of by a proembryonal cell, but the number of free nuclei formed by — 
the egg in each case is approximately the same. | 
INTEGUMENTS ‘ 
The mature seed of Gnetum Gnemon gives an opportunity 1? : 
compare the integument and testa with those of other gymnosperms. 
Fig. 6a shows the seed slightly stalked within the so-called “perianth,” 
which is fleshy. Two integuments are evident, and they develop in 3 
S LAND, W. J. G., Fertilization and : ° ts 
x ds embryogeny in Ephedra trifurca. BOT 
GAZETTE 44:273-292. pls. 20~22, 1go7. . J pare we a 
