HOW TO DISSECT A FLOWEE. 
149 
in the two sets of floral leaves is very distinct ; whilst in the tulip, 
for example, the difference can scarcely be detected. It must 
be remembered that in this examination the single snowdrop is 
under inspection, and not the cultivated form known as the 
double snowdrop. 
In some flowers having a perianth of this character, one or 
more of the petals have a form that differs from the rest, as in 
orchids, and such a perianth is called irregular. In the present 
instance, although the petals and sepals differ in size and form, 
they are alike in each series, so that the snowdrop has a regular 
perianth. 
Within the perianth are six stamens, or two series of three 
in each, and all of the same length. Three of these are 
opposite to the three outer segments or sepals, and three are 
opposite to the three inner segments or petals. The filaments 
are short and the anthers are long, two-lobed at the base, and 
attenuated upwards to a sharp point (fig. 31), opening by a 
longitudinal fissure on the inner face. The pollen grains are 
irregular in form, mostly elliptical, often curved, with a longi- 
tudinal groove (fig. 37). Their surface appears to be smooth. 
The centre of the flower is occupied by the pistil, which is 
slightly attenuated upwards, and not surmounted by any visible 
head, knob, or projection (fig. 33). Only the apex has free 
capitate cells, with a more distinct head than the hairs of the 
stigma in the primrose. These are only to be seen with a high 
power under the microscope. If the style is squeezed flat in a 
drop of water between two strips of glass, a number of small 
crystals (raphides), slender, and pointed at each end, will be set 
free (fig. 34). 
To examine the ovary it will be necessary to make two sec- 
tions — one longitudinally through the entire flower (fig. 30), and 
one transversely across the ovary (fig. 32). The longitudinal 
section will show that the ovary is inferior, bearing upon it the 
stamens and petals ; it will also exhibit the axis passing quite 
through the ovary, and not stopping short as in the primrose. 
It will not be easy to cut through the ovary in such a manner 
that the ovules will be seen on both sides of the centre. The 
reason of this will be more obvious when a transverse section is 
made. A section of the latter kind shows that the ovary con- 
sists of three cells, each of which contains ovules attached to the 
centre or axis (fig. 32). The ovules are elongated, beaked at 
one extremity, and with a minutely reticulated surface (fig. 36). 
Numerous ovules are contained in each cell. 
To summarise the results of this examination, we discover 
that the flower just dissected has a regular perianth with six 
segments, of which the three inner are smallest, and notched. 
The stamens are six, sharp -pointed, all of the same length j 
