. A handbook of cryptogamic botany. Cryptogams. FILICES 67 archegones being produced later, and in smaller numbers, on female pro- thallia ; or the same prothallium may produce first antherids and sub- sequently archegones, when it may be termed proterandrous. This is remarkably the case also in Gymnogramme. In Cystopteris firagilis (Bernh.) (Polypodiaceae) Campbell states that there are two kinds of prothallium, a smaller male and a larger hermaphrodite. The prothal- lium of ferns is sometimes propagated vegetatively by the production of adventitious shoots from single marginal cells, which b
. A handbook of cryptogamic botany. Cryptogams. FILICES 67 archegones being produced later, and in smaller numbers, on female pro- thallia ; or the same prothallium may produce first antherids and sub- sequently archegones, when it may be termed proterandrous. This is remarkably the case also in Gymnogramme. In Cystopteris firagilis (Bernh.) (Polypodiaceae) Campbell states that there are two kinds of prothallium, a smaller male and a larger hermaphrodite. The prothal- lium of ferns is sometimes propagated vegetatively by the production of adventitious shoots from single marginal cells, which become detached and form independent prothallia. This takes place especially in Hymenophyllacese and in Osmunda, btit occurs also in Polypodiaceae,.. Fig. 45.—Archegone of Adia-ntum capilhts- Veneris^ in various stages. _ -4, j5, C, .E, in longitudinal, D in transverse section ; h, neck ; sl^ canal-cells converted into mucilage ; j, ventral canal-cell; e, 'oosphere ; in B divided into a 2-celled embryo (x 800). (After Goebel.) abundantly in Gymnogramme (see Cramer, Denkschr. Schweiz. Naturf. Gesell., 1880). The prothallium of Vittaria (Sm.) produces peculiar stalked bulbils. The antherids of ferns are small papilliform projections on the under side or margin of the prothallium (very rarely on the upper side), produced among the rhizoids, and of similar origin, from a single superficial cell ; in the Hymenophyllacese they are produced also on the protonemal filaments. The protuberance becomes separated by a septum from the parent superficial cell, and then sometimes divides at once into the parent-cells of the antherozoids. But more often the. 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 Bennett, Alfred W. (Alfred William), 1833-1902; Murray, George Robert Milne, 1858-. London, New York, Longmans, Gr
Size: 1871px × 1336px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondonnewyorklongm
