. La structure et le développement de mousses et de fougères (Archegoniatae). La morphologie des plantes, mousses, fougères. X LE LEPTOSPORANGIATX HOMOSPORÉES 39i e. g., Alsophila contaminans, le tronc est tout à fait libre à partir des racines, et les feuilles tombent, laissant des cicatrices très caractéristique marquée par les faisceaux vasculaires. Dans d'autres, comme Dicksonia ant- arctica, tout le tronc est recouvert d'un épais tapis de racines, plus épais que le coffre lui-même. Le prothalle est exactement comme celle de l'Polypodiaceae, tant qu'elle a été étudiée (Bauke (i)), sauf que chez certaines espèces d'il y a des soies Alsophila curieux comme ha

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. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. X THE HOMOSPOROUS LEPTOSPORANGIATX 39i e. g., Alsophila contaminans, the trunk is quite free from roots, and the leaves fall away, leaving very characteristic scars marked by the vascular bundles. In others, like Dicksonia ant- arctica, the whole trunk is covered with a thick mat of roots, thicker than the trunk itself. The prothallium is exactly like that of the Polypodiaceae, so far as it has been studied (Bauke (i)), except that in some species of Alsophila there are curious bristle-like hairs upon the upper surface. In the structure of the antheridia the Cyathe- acese are intermediate in character between the Polypodiaceae and the Hymenophyllaceas. The characteristic funnel-formed. Fig. 229.—A, Part of a sporophyll of Thyrsopteris elegans, X2; B, section of the sorus, Xio; C, leaflet, with two sori, of Cyathea microphylla. (A, B, after Kunze; C, after Hooker.) primary wall of the former occurs Here, But not until one and sometimes two preliminary basal cells are cut off, as in Os- munda or Hymenophyllum. The following divisions corre- spond exactly with those of the antheridium of the Polypodi- aceae, except that Bauke states that the cap cell, as well as the upper ring cell, may divide again. The dehiscence is effected either by the separation of an opercular cell or by the rupture of the cap cell. The archegonia are like those of the Polypodi- aceae. In Cyathea medullaris Bauke figures a specimen, how- ever, where the neck canal cell is divided by a membrane (1. c. PL IX, Fig. 8). The first divisions in the embryo correspond with those of the Polypodiaceae, but the further development of the young sporophyte is not known.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Campbell, Douglas

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