Morphology of the edible fernAmpelopteris kunze

Abstract

Morphology of the sporophyte and gametophyte ofAmpelopteris prolifera is described. The rhizome is dichotomously branched, short creeping and nearly naked except at the apex where it bears small basally attached, gland-tipped paleae bearing deciduous acicular as well as glandular marginal hairs. The parenchymatous ground tissue includes a few scattered partially thick-walled cells. The vascular cylinder is a radio-symmetric dictyostele dissected into narrow meristeles by spirally disposed leaf gaps, each associated with a pair of ribbon-like leaf trace bundles. Leaves are pinnate; most vegetative leaves on adult plants grow indefinitely and proliferate profusely by means of vegetative buds borne in the axils of some of the pinnae. The vascular connection to the bud is fused with that of the associated pinna and originates as a hollow cylindrical extramarginal strand from the rachis bundle. The stipes (when young) and rachis bear characteristic, branched, unicellular, club-shaped hairs; elongated acicular hairs are found on the veins and on young lamina. Venation is goniopteroid. Sori are exindusiate, elongated and borne on the secondary veins. The sporangium is leptosporangiate and commonly bears 1 or 2 large glandular hairs on the stalk. The spores are bilateral, with smooth exine and granulose perine. On spore germination a uniseriate germ filament is produced, which develops into a cordate prothallus by forming a wedge-shaped meristematic cell in its terminal cell. The mature prothallus is cordate, with a thin midrib and broad wings. Young prothalli are naked. Aspidiaceous hairs are produced on the surfaces and margin towards maturity; sparse unicellular acicular hairs are often found on the margin of the mature prothallus. Sex-organs are of the common leptosporangiate type. It is concluded thatAmpelopteris is closely related toCyclosorus and that its separation as a genus fromGoniopteris does not seem to be justified.