. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. EMBRYOLOGY 303 By this means rapid growth of the root (Fig. 169, B, ;â .) takes place, and it soon pierces the prothallus and penetrates into the soil. Simultaneously the first leaf (/.), carrying with it the still rudimentary stem (s.), emerges on the lower side, and, arching up through the notch at the front end of the heart-shaped pro- thallus, exposes its green blade to the light. The stem now grows more vigorously, giving rise to adventitious roots which. Fig. 168.âa-c, archcgonia, e,/, and^, antheridia,
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. EMBRYOLOGY 303 By this means rapid growth of the root (Fig. 169, B, ;â .) takes place, and it soon pierces the prothallus and penetrates into the soil. Simultaneously the first leaf (/.), carrying with it the still rudimentary stem (s.), emerges on the lower side, and, arching up through the notch at the front end of the heart-shaped pro- thallus, exposes its green blade to the light. The stem now grows more vigorously, giving rise to adventitious roots which. Fig. 168.âa-c, archcgonia, e,/, and^, antheridia, and d, single spermatozoid of the Fern. a, immature, and b, mature, archegonium in longitu- dinal section ; c, neck in surface view. 0., egg ; , ventral canal cell, g, almost mature antheridium in optical section, showing the wall {w.) and the spermatozoid mother-cells (s.) ; e, dehiscing antheri- dium with the escaping spermatozoids ; /, dehisced antheridium from above, [a after Goebel ; the remainder after Knv.) replace the short-lived primarj' root, and it is not long before further leaves develop (Fig. i6g, C). The latter, however, show but a very gradual increase in complexity, from the first, often almost undivided leaf, to the normal compound foliage of the adult Fern, which is frequently only attained after the lapse of several years. Production of sporangia is generally deferred till this stage is reached. The young Fern, like the sporophyte of Liverworts and Mosses, is thus for a time dependent for nourishment on 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
Size: 1889px × 1322px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
