1871.] 
GARDEN LITERATURE. 
21 
plantation should be performed with care ; and if done under the favourable 
circumstances of a warm soil and moist atmosphere but little injury ensues, as 
the plant is speedily enabled to form new absorbent extremities. The absorption 
of food by the youngest 1 'ootlets is due to osmose taking place between the 
contents of their cells and the fluids of the surrounding soil. The absorption of 
food taking place almost entirely near the extremities of the roots, the latter are 
placed in the most favourable conditions to obtain that food, because in their 
progress they constantly advance into new soil. Moreover, experiment has shown 
that when roots meet with an increased store of nourishment in the soil, a greatly 
increased development of rootlets and fibrils takes place for its absorption. 
On the subject of plant fertilization, our space only permits us to extract a 
few sentences having reference to the subjoined woodcuts. Pollen-cells (figs. 
Fig. 3. Pollen-cell discharging its fovilla; 4. Pollen-with pollen-tube; 5. Vertical section of stigma (stig.J, on 
which two pollen-cells have fallen, each provided with a tube (tp), which pierces the tissue of the style 
(styl.); 6. Section of ovule: t, enlarged end of pollen-tube containing fovilla, which has entered the 
micropyle, and is seen pressing towards the apex of the embryo sac; sr , fertilized germinal vesicle, 
which already begins to exhibit two parts, the upper, s, forming a suspensor, the lower, r, a globular 
body, which ultimately becomes the embryo; e , endosperm cells or albumen ; 7. Section of ovule: f, 
enlarged end of pollen-tube, closely applied to the embryo sac; e, germinal vesicle fertilized, the lower 
portion being the rudimentary embryo. 
3, 4) when moistened become distended in consequence of endosmotic action. 
If this action is continued the cells burst, but as the intine is very extensible, 
while the extine is firm and resisting, the intine will form little projections 
through the pores of the latter, producing on the surface blister-like swellings, 
which ultimately burst and discharge the contents of the cell in the form of a 
jet (fig. 3). 
“When the pollen falls upon the stigma (the tissue of which at this period, as well as that 
forming the conducting tissue of the style and neighbouring parts, secretes a peculiar viscid 
fluid), its intine protrudes through one or more of the pores or slits of the extine (fig. 4) in the 
form of a delicate tube, which penetrates through the cells of the stigma, by the viscid secretion 
by which it is nourished. In most plants but one pollen-tube is emitted by each pollen-cell, but 
the number varies.The pollen-tube continues to elongate by growth at its apex, and 
passes down through the conducting tissue of the canal of the stylo (fig. 5 tp ), when this exists, 
or directly into the ovary when it is absent. This growth of the tube was formerly supposed 
to be due to endosmotic action occurring between the contents of the pollen and the secretion 
of the stigma and style; but it is now known to be a true growth, which is occasioned by the 
nourishing viscid secretion which it meets with in its passage through the stigma and style. 
“ These tubes are extremely thin. They vary hi length according to circumstances, but are 
