86 
PLANTS AND INSECTS 
We were astonished at what seemed to us such peculiar behavior 
of ants and determined to learn something about these interesting little 
creatures. 
PROPAGATION OF FERNS 
44TJERE they are at last!” exclaimed Helen, as she observed the 
A A large fern in the sitting-room more closely than she had done 
for several weeks. “I have looked for them many timles, and wondered 
why I could never find them. ’ ’ 
‘ “What?” inquired Elsie as she drew nearer to the beautiful green 
plant, all the more appreciated because the out-of-doors was buried be¬ 
neath the snow. 
“Do you see these little brown spots arranged in rows on the under¬ 
side of the fronds? They are sori and contain spores,” replied Helen. 
“You mean seeds/’ spoke up another girl, and at once the inter¬ 
esting way in which ferns propagate was under discussion. 
The brown dots were not seeds, neither did they contain seeds, 
for ferns do not bare seeds. They were collections of spore-cases, and 
every wee spore-case held many, mlany tiny spores, each of which, under 
favorable conditions, was capable of producing a tiny plant; not a fern, 
however, for ferns do not, grow from spores. 
All ferns bear spores, but various species have different ways of 
arranging and protecting their spore-cases. In some species each little 
group, or sorus, is covered with a thin scale, or shield, while in others 
the sori are protected by the edges of the fronds turned back or by the 
contraction of the entire frond. 
When the spore-case is ripe, it bursts and scatters the spores 
broadcast. If you wish to see some of these spores, lay a mature fruit¬ 
ing frond, top side up, on white paper, and allow it to remain in a dry, 
warm place. The spores will discharge on the paper. A spore falling 
in a moist, warm place develops into a heart-shaped, green, leaflike 
body known as the prothallium, which sends forth roots into the ground. 
Sometimes the prothallium is an inch or more across, but oftener it is 
less than one fourth that size. It bears on its undersurface two kinds 
of cells, corresponding to the ovules and pollen-grains of seed-bearing 
plants. These cells unite, and, as in the case of the union of pollen-grain 
and ovule among flowering plants, a new plant, is the result. Bnt the 
