POLLEN-BODIES OF THE ANGIOSPERMS. 
29 
the nucleus of the vegetative cell (figs. 45, 46). It, however, 
also happens that the latter may remain behind in the 
Pollen-body (fig. 48). The vegetative nucleus divides later 
on in the tube, and this occurs botli when it is in front 
as well as when it is behind (figs. 45, 47). I never found it 
thus dividing while in the Pollen-body. 
In P'othos Olfersii the two nuclei are similar also, being 
both elliptic and lying beside one another. 
Not to mention the division of the vegetative nucleus in the 
Pollen-tubes of the Orchids and in Sparganium, I found that 
division of the vegetative nucleus may occur in Iris xiphiumy 
and a duplication of the vegetative cell itself in the Pollen- 
body of Tiilipa gesneriana. In these species this is excep- 
tional. In some Monocotyledons such a formation of several 
vegetative cells is normal. This is well seen i\\ Andropogon 
campanus. The Pollen-bodies of this species are spherical, 
with a thin extine which, as-in all the Gramineae, is pierced 
by a small orifice, through which later the inline grows out 
into a tube. In the stage of development in which the 
vegetative cell is formed, the Pollen-body contains only a 
thin parietal layer of finely granular protoplasm, surround- 
ing a large vacuole. These Pollen-bodies are very favor- 
able objects for examination, as starch and other bodies 
sometimes enclosed in protoplasm are altogether absent. 
Indeed, I have found no other plant which showed the 
formation and development of the vegetative cell so 
plainly, without making use of reagents. Pollen-bodies can 
be found in almost every anther ; even in blossoms which 
are already ripe for pollination many Pollen-bodies appear 
in a retarded state. 
Originally the Pollen-body carries only one single nucleus 
with a nucleolus. A small vegetative cell is then formed 
diametrically opposite the orifice in the extine. It is of the 
usual shape with clear protoplasm, and with a spherical or 
oval nucleus, which is provided with a small but distinct 
nucleolus. The nucleus of the large cell is generally 
disk-shaped, and has a large, strongly refractive nucleolus 
(figs. 54, 55). Typically, the vegetative cell next divides 
itself into two equal sister-cells, one of which often divides 
a<zain, so that we have finally three vegetative cells (figs. 58, 
59). The nucleus of the large cell remains unchanged. 
AVhen this is over the protoplasm increases in volume and the 
Pollen-body fills itself with starch grains. Soon the vege- 
tative cells are detached and float about freely (figs. 60, 
61). Before the Pollen-bodies reach their ripe condition 
several nucleoli are absorbed, the nuclei themselves undergo 
