. The structure and development of mosses and ferns (Archegoniatae). Fig. 151.—Marattia Douglasiu A, Prothallium about one year old, X2; B, the sameprothallium about a year later, showing a dichotomy of the growing point; C, thesame seen from below, showing two archegonial cushions (^); D, prothallium withyoung sporophyte, X4; E, a somewhat older one, seen from the side; r, the pri-mary root. organs upon It forks with it, exactly as we find, for example,the antheridial receptacle forking in Fimbriaria Californica(Fig. I, A). Besides this form of branching, which is notcommon, adventitious buds
. The structure and development of mosses and ferns (Archegoniatae). Fig. 151.—Marattia Douglasiu A, Prothallium about one year old, X2; B, the sameprothallium about a year later, showing a dichotomy of the growing point; C, thesame seen from below, showing two archegonial cushions (^); D, prothallium withyoung sporophyte, X4; E, a somewhat older one, seen from the side; r, the pri-mary root. organs upon It forks with it, exactly as we find, for example,the antheridial receptacle forking in Fimbriaria Californica(Fig. I, A). Besides this form of branching, which is notcommon, adventitious buds are produced upon the margin ofthe thallus very frequently. These grow^ in precisely the sameway as the main prothallium, and after a time may become 278 MOSSES AND FERNS chap. detached and form independent plants; or they may developsexual organs (mainly antheridia) while still connected withthe mother plant. The duration of the prothallium is apparentlyunlimited, so long as it remains unfecundated. The writerkept prothallia of Marattia Douglasii for nearly tw
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Keywords: ., bookauthorcampbelldouglashought, bookcentury1900, bookdecade1910
