Elementary botany . elementarybotany00atki Year: 1898 Fig. 215. Spore of Pteris serru- lata showing the three- rayed elevation along the side of which the spore wall cracks during germination. vicinity of ferns, we would probably find tiny, green, thin, heart- shaped growths, lying (-lose to the substratum. These are also found quite frequently on the soil of pots in plant conservatories where ferns are grown. Gardeners also in conservatories usually sow fern spores to raise new fern plants, and usually one can find these heart-shaped growths on the surface of the soil where they have sown th
Elementary botany . elementarybotany00atki Year: 1898 Fig. 215. Spore of Pteris serru- lata showing the three- rayed elevation along the side of which the spore wall cracks during germination. vicinity of ferns, we would probably find tiny, green, thin, heart- shaped growths, lying (-lose to the substratum. These are also found quite frequently on the soil of pots in plant conservatories where ferns are grown. Gardeners also in conservatories usually sow fern spores to raise new fern plants, and usually one can find these heart-shaped growths on the surface of the soil where they have sown the spores. We may call the gardener to our aid in finding them in conservatories, or even in growing them for us if we cannot find them outside. In some cases they may be grown in an ordinary room by keeping the surfaces where they are growing moist, and the air also moist, by placing a glass bell jar over them. 366. In fig. 214 is shown one of these growths enlarged. Upon the under side we see numerous thread-like outgrowths, the rhizoids, which attach the plant to the substratum, and which act as organs for the absorption of nourishment. The sexual organs are borne on the under side also, and we will study the m a t e r. This heart-shaped, flattened, thin, pore and green plant is the pruthdllium of ferns, and we should now give it more careful study, be- ginning with the germination of the spores. 367. Spores.—We can easily obtain material for the study of the spores of ferns. The spores vary in shape to some extent. Many of them are shaped like a three-sided pyramid. One of is shown in fig. 215. The outer wall is roughened, and on one end are three elevated ridges which, radiate from a given Fig. 216. Spore of Adiantum acrostichoides with winged exospore. Fig. 217. Spore crushed to remove e: show endospore.
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