POLLEir. 
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feometimes wanting ; when present it proceeds from the ovary, 
and bears the stigma on its summit ; it is usually long and 
slender, of a cylindrical form, consisting of bundles of fibers, 
which transmit to the ovules, from the stigma, the fertilizing 
poiien. The stigma is the continuation of the cellular tissue in 
the center of the style. The stigma is always present ; if the 
style be wanting it is placed upon the germ, and said to be ses- 
sile^ as in the tulip. The stigma is various in size and form : 
sometimes it is a round head ; sometimes hollow and gaping, 
more especially when the flower is in its highest perfection ; it 
is generally downy, and always more or less moist, with a 
peculiar viscid fluid. 
a. Fig". 87, A, represents the pis- 
til of the Cynogloscium; style cylin- 
dric, stigma depressed or flattened 
at the top; four ovaries, contain- 
ing rudiments of seeds. B repre- 
sents the pistil of the Tournefortii, 
stigma hemisphericnl, sub-sessile, 
surrounded with a glandular hood. 
C represents the pistil of the 
Helitropium ; a, four ovaries ; h, a 
short style ; e, a conical, four-part- 
ed stigma. D represents a pistil 
of the genus Cucumis; a is the 
ovary adhering to the calyx; 6, 
three abortive stamens; c, cyiin- 
dric style ; </, three-lobed stigma ; 
E, pistil of the genus Rumex ; a «, 
plumose stigmas, with three car- 
pels at the base. 
81. The Pollen, which in most flowers is a kind of farina, or 
yellow dust, is thrown out by the bursting of the anther, which 
takes place in a certain stage of the flower. This discharge of 
pollen is owing to the formation of a tissue of fibers from the 
cellular lining ; which fibers, by being coiled or interwoven, 
form minute springs that by their mechanical force open the an- 
ther and scatter the pollen. The pollen is very curiously form- 
ed ; although appearing like little particles of dust, upon exam- 
ining it with a microscope it is found to be composed of innu- 
merable organized corpuscles. These, though usually yellow, 
are sometimes white, red, blue, &c. They are oblong in the 
Umbelliferous plants, glohidar in the Syngenesious, and t/rian- 
gular in some others. In some their surface is smooth, in others 
armed with little points. They are connected together by mi- 
nute threads, as in the honeysuckle, &c. These particles of 
pollen when placed upon water swell with the moisture until 
they burst ; a liquid matter is then thro^vn out, and, expanding 
upon the surface of the water, appears like a light cloud. 
Stigiua— a. Explain Fig. 87.— 81. PoUeu. 
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