A handbook of cryptogamic botany / by Alfred W. Bennett and George Murray.

  • Alfred William Bennett
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: A handbook of cryptogamic botany / by Alfred W. Bennett and George Murray. Source: Wellcome Collection.

    101/492 (page 89)
    The sessile or shortly stalked, roundish, but unsymmetrical sporanges are not strictly epidermal in their origin. They bear on one side of their apex a modified annulus in the form of a group of cells of peculiar form, and dehisce vertically on the other side. Todea (Willd.) presents no difference between the fertile and sterile leaves ; while in Osmunda(L.)the fructification has the appearance of a con- tinuous or interrupted panicle, F ig. 67.—Mucilage-gland from Osmunda regalis (magnified). (After Gardiner.) from the entire absorption of the mesophyll of the fertile part of the leaf. In some species of Todea the leaf con- sists of only a single layer of cells. In Osmunda there are Portion of frond Fig. 68.—Sporange of Osmunda (magnified). abundant mucilage-cells at the base of the leaf-stalk. The ‘vascular ’ bundles of the stem are collateral, as con- trasted with the concentric bundles of typical ferns, and their course bears more resemblance to that in Gymnosperms and in Dicotyledons. In the structure of the leaves, and in the structure and development of the growing point, Osmundacete exhibit a transitional condition between the typical ferns Fig. 66.—Osmunda regalis L. (natural size).