REPRODUCTION 47 
period of several years? Of what advantage is it for these 
plants to reproduce in this way? 
Determine the number of new plants that can be pro- 
duced from one of the potato-tubers. Is the average num- 
ber about the same with sweet potatoes as with white po- 
tatoes ? 
In clean, damp sand plant slips of coleus, begonia, ge- 
ranium, willow, cottonwood, eyes of potatoes, and bulblets 
of onions or tiger-lily. Keep the sand moist, and observe 
some of the specimens from day to day to see how soon they 
begin to establish themselves as new plants. Find how 
small a piece of begonia er willow will develop into a new 
plant. 
LESSON XX'V 
Reproduction by spores in mosses and ferns 
Materials—Moss plants bearing ripe capsules and vari- 
ous ferns with ripe sporangia. 
Mosses.—The leafy shoot has on its tip a long stalk at 
the end of which is the capsule in which the spores are 
formed. At the end of the capsule is an adjustment by 
means of which spores are discharged. Carefully cut off 
the tip of the capsule, mount it so that it may be seen 
from an outside view, and note its covering and the teeth 
which project inward from immediately beneath the margin 
of the covering. Mount an old capsule so that it may be 
seen from a side view, and note the position of the teeth. 
Can you determine how they assist in spore discharge? 
1 Tf favorable locations are near, a field study should be made 
of vegetative reproduction. In addition to points mentioned above, 
the students should notice vegetative reproduction in the strawberry, 
the raspberry, also several plants that will probably be found in any 
swampy region. It would be instructive to dig up some of the under- 
ground stalks to see their extent and the number of new plants they 
are establishing. 
