200 PRACTICAL COURSE IN BOTANY 
or of the lobes of the ovary. Examine the tip with a lens 
and notice the sticky, mucilaginous exudation that moistens 
it. Can you think of any use for this? If not, touch one of 
the powdery anthers to it, and examine it again with a lens. 
What do you see? Can you blow or dust the pollen from 
the stigma? 
215. Pollination, or the transfer of pollen from the anther 
to the stigma, is a matter of great importance, as the pistil 
cannot develop seed without it, except in the case of a few 
plants like the Alpine everlasting, some species of meadow 
rue (Thalictrum), and Alchemilla, which have the unusual 
faculty of perfecting seeds in the absence of pollen. Note 
the relative position of pistils and stamens and see if it is 
such that the pollen can reach the stigma without external 
agency. 
216. The ovary. — Observe the shape of the ovary, and 
the number of ridges, or grooves, that divide the surface. 
Select a flower which has begun to 
wither, so that the ovary is well 
developed, cut a cross section near 
the middle, and try to make out the 
number of locules, or internal divi- 
sions. Do you perceive any corre- 
spondence in number between these 
279 
280 
Fies. 279, 280.— Ovary of 
yucca, a hypogynous mono- 
cotyl, dissected: 279, vertical 
section ; ov, ovules ; 280, diagram 
of a horizontal section of the 
and the ridges or lobes outside (Fig. 
280)? Between them and the lobes 
of the stigma? The walls that 
inclose the cavities of the ovary 
same, enlarged, showing the 
three carpels and six locules ; 
ds, dorsal sutures; vs, ventral 
sutures; ov, ovules; pl, pla- 
centa. 
are called carpels, and the ridges or 
depressions that mark their point 
of union on the outside are the 
sutures, orseams. The little round 
bodies in the locules, as the compartments of the ovary are 
called, are the ovules, which will later be developed into seeds. 
Their place of attachment is the placenta. If they are 
attached to the walls of the carpels (Fig. 281), the placenta 
