1897 THE MICROSCOPE. 35 
water runin. ‘The moisture is absorbed by the pollen 
grain, and it throws out a tube and discharges the for 
villa. It goes off like a little cannon, a cloud of fovilla 
waving on the slide. To see the actual pollen-tubes in 
their passage down the style ss a more difficult matter ; 
nevertheless it can be done. Use a ¢ inch objective and 
choose a flower with a stout style, such as the Cistus or 
Chickweed; the flower must have just faded, when you 
may be sure the ovules are fructified. With a sharp ra- 
zor make a very thin section of the pistil, and lift it with 
a fine sable brush onto a slide in a drop of water, cover, 
and focus carefully, have a good light, and you will see 
the pollen tubes actually descending the tissue of the 
style. We see how varied are the lengths of styles and 
pistils, yet the pollen-tube stops not until it reaches the 
ovary, and, when there, it seeks the one spot in each ovule 
by which alone if can enter, and there, and there only, 
it rests. Thus we see the all directing power even in 
the tiniest flower. 
The quantity of pollen ina flower is astonishing. The 
Peony has 174 stamina, each containing 21,000 granules, 
a total of 3,654,000 pollen-grains. A single dandelion - 
has 243,000 pollen-grains. Although there are so many 
they are not wasted, as they furnish food for insects. 
The pollen-grains can be examined as a transparent 
object with a drop of water or oil of lemon, and dry as 
an opaque object. Particularly interesting are the blue 
pollen of Epilobium; the red pollen of Verbascum, and 
‘the black pollen of the Tulip. 
The following are of interest: Crocus, Cactus, any of 
the Crucifere, Collomia, Campanula, Cobe#a, Scandens, 
any of Composite, Geranium, Daisy, London Pride, Saxi- 
frage, Mallow, Violet, Ginothera, Passion-flower, Lupen, 
Accacia, Convolvulus, Hollyhock, Primrose, Flax, Musk- 
plant, Nasturtium, St. Johnswort, Sowthistle, Rush, 
Crowfoot, Snow-drop, Apple and Lily. 
