Page:Parsons How to Know the Ferns 7th ed.djvu/54

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Polypody

EXPLANATION OF TERMS


A fern is a flowerless plant growing from a rootstock (a), with leaves or fronds usually raised on a stalk, rolled up (b) in the bud,[1] and bearing on their lower surfaces (c) the spores, by means of which the plant reproduces.

A rootstock is an underground, rooting stem. Ferns are propagated by the growth and budding of the rootstock as well as by the ordinary method of reproduction. The fronds spring from the rootstock in the manner peculiar to the species to which they belong. The Osmundas, the Evergreen Wood Fern, and others grow in a crown or circle, the younger fronds always inside. The Mountain Spleenwort is one of a class which has irregularly clus-

  1. Ophioglossum and the Botrychiums, not being true ferns, are exceptions.

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