. Carnegie Institution of Washington publication. 206 THE MARATTIALES case and that the tapetal cells persist until the division of the spores is complete. Bower has confirmed this statement and found that the same condition of things obtains in the other genera. The most complete account of the development of the sporangium is that of Bower (Bower 6), who has studied the development in all of the genera except Archangiopteris. Except for the difference in form, there is no essential difference in the development of the sporangia in Kaulfussia and Daneea from that found in Marattia. In Daneea,
. Carnegie Institution of Washington publication. 206 THE MARATTIALES case and that the tapetal cells persist until the division of the spores is complete. Bower has confirmed this statement and found that the same condition of things obtains in the other genera. The most complete account of the development of the sporangium is that of Bower (Bower 6), who has studied the development in all of the genera except Archangiopteris. Except for the difference in form, there is no essential difference in the development of the sporangia in Kaulfussia and Daneea from that found in Marattia. In Daneea, however, the individuality of the loculi of the synangium is less clear than in the other genera. Very often Bower found that the arche- sporium became divided more or less completely by parts of the sterile tissue, some- what in the same fashion that the so-called "trabecular" are formed in Isoetes. In Daneea, moreover, the synangium from the first is solid, and the cleft which is present in the young synangium of Marattia is absent. In Kaulfussia the develop- ment of the synangium differs in that a single circular ridge is formed instead of the. Fio. tS. A. Section "I -i young synangium "l Marattia fraxinca. â iz^. B, Locului from an older synangium. x, the tapctum (after Bower). two parallel oiks found in Marattia, and the loculi or chambers of the synangium are thus arranged in a circle around a central pit-like depression. Bower states that the sporogenous tissue of each loculus in all the forms he examined can usually be traced to a single mother cell. He also found that the tapetum always arises from the cells adjacent to the a i chcsporium, and that normally all of the sporogenous tissue develops into spores. In these respects the Marattiaceae closely resemble Helminthostachys and Botrychium. In Daneea and there is no mechanical tissue representing the annulus found in the more specialized terns. The dehiscence of the sporangium in these
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