310 PRINCIPLES OF BOTANY, ETE. 
sary food from the atmosphere, and convey it to the 
receptacle to which the flower is attached. 
The nectaries, (§ 81), if not composed only of 
elands, agree in their structure with the corolla. 
§ 287. 
‘The stamens, (§ 86—-88), consist of the filament 
and anther. They are likewise called the male organs 
of fructification. The filament, in the distribution of 
of its vessels, resembles either the herbaceous stem, 
or the leaves, according to the variety of its shape, 
which differs very much, but in each plant com- 
monly bears a peculiar but constant character. The ' 
anthers are formed of a thin, but vascular mem- 
brane, filled with pollen. 
“The pollen itself occurs under a variety of forms, 
which can only be seen with a microscope. Messrs. 
Jussieu, Du Hamel, Needham, Gleichen, and others, 
found, when viewing the pollen with a high magni- 
fying microscope, that its globules, when brought 
in contact with water, burst with a degree of violence 
and emitted a gelatinous mass. Koelreuter, on the 
contrary, assures us, that ripe pollen does not burst 
so suddenly when wetted, but slowly emits through 
its pores, or if provided with small prickles, through 
those, an oily fluid, which on the surface of water 
forms a distinct shining pellicle. He says further, 
that each single globule of the pollen consists of two 
membranes; anexternal one, which is thick, elas- 
tic, cartilaginous, and full of very delicate vessels, 
which last are said to contain the pores which emit 
| the 
