Who's Who Among the Ferns (Classic Reprint) - Hardcover

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Excerpt from Who's Who Among the Ferns<br/><br/>On the under side of the fronds of most species numerous small dots may be found. These are sometimes erroneously called the ?owers of the fern, though structurally, they bear no resemblance to ?owers. These small bodies termed fruit dots or sari (singular sorus) constitute the fruiting or gans of the fern. In their earlier stages they are, in most species, covered with a membrane called the indusium (plural indusia) which protects a col lection of tiny globes called sporangia (singular sporangium). The indusium at the proper time withers and disappears, exposing the sporangia. In each sporangium is produced a large number Of tiny bodies called spores, which are liberated at maturity by the snapping open of the sporangia or spore  cases, and from these spores, under f avor able circumstances, the new plants arise. In View of this fact the natural inference might be that they are seeds, but they bear no more resemblance to seeds than the sori do to ?owers. They only correspond to seeds inasmuch as they serve to carry the plants through a resting stage, and scatter the species far and wide. A germinating spore does not give rise immediately to a plant like the parent as true seeds do. Instead, it develops into a small, ?at, green, heart  shaped body, scarcely a quarter of an inch across, called the prothallium (plural prothallia) (fig. I). On the under side of the prothallium are borne two minute organs, and by the union of their contents a tiny fern develops.

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