The thin wiry roots spring from the bases of the leaf-stalks, just where these come off the stem.
Fig. 146.—The Male-Fern. 1, Illustration showing general habit (× ¹⁄₁₀); a, young leaves: 2, cross section of stem showing conducting bundles a: 3, portion of leaf; b, spore-boxes; a, covering scale: 4, longitudinal, and 5, cross section of group of spore-boxes; a, leaf; b, scale; c, spore-boxes: 6, a single spore-box; a, stalk; c, spring; d, spores.
The leaves or fronds of the male-fern arise near the growing-point (the upper end) of the stem. Leaves of almost all ages are present. Those which surround the growing-point are mere rudiments; while slightly older ones ([Fig. 146], 1, a) are tightly rolled up into a coil. During their growth the coils unfold, the inside of the coil becoming the upper surface of the leaf. A fully expanded leaf is roughly triangular in shape. The leaf-stalk and the midrib are covered with brown, scaly hairs; and the blade of the leaf is divided into several distinct leaflets, which are arranged on the midrib in two rows. The leaflets are also in many cases sub-divided into separate segments.
The spores.—On the lower surface of many of the segments of a male-fern frond may be seen a number of small, brown, kidney-shaped scales ([Fig. 146], 3, a). Each scale is attached to the leaf by a short stalk, and the structure thus bears a rough resemblance to a little umbrella. Attached to the bottom of the short “handle” of the “umbrella” are several tiny boxes, somewhat like pill-boxes. These are shown at b ([Fig. 146], 3), and highly magnified at 4 and 5. [Fig. 146], 6, represents a single box, more highly magnified. When ripe, each box contains about fifty minute grains, which may thus be likened to the pills in the pill-boxes. These “pills” are called spores. Summing up thus far, we may say that the spores are formed in spore-boxes, which are attached by stalks to the lower surface of the frond, each group of spore-boxes being covered by a protective scale.
The scattering of the spores.—When the spores are ripe, each box ([Fig. 146], 6) becomes dry, and is ultimately burst by the sudden straightening of a spring (c) which is coiled round its edge. The force of the uncoiling of the spring is sufficient to jerk the spores (d) out of the box into the air, and they may be carried for some distance by the wind before they at length reach the ground. Once there, however, each spore, under favourable conditions, begins to grow, and gives rise to a plant which, curiously enough, is not in the least like the parent fern plant which produced the spore.
The difference between a spore and a seed.—It is important to notice that the spore is produced by a purely non-sexual process. In this respect it differs widely from the seed of a flowering plant, which, it will be remembered ([p. 92]), results from the union of the living matter of a pollen grain with that of an ovule.
