. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 16 mopiPttoloitY of sperjiatopiiytes The first indication of a megasporana'inm is the differentia- tion of a gronp of sj-Kirogenons cells innnediatelv beneath the epidermis. It is not a liypodernial jilate. as in the niicrosporan- ginni, bnt a hypodernial mass of cnsideralile extent. AVhether this gronp represents the archesporiTun, or whether it can be traced hack to a few-celled or even to a one-celled arcliesporinm, is still in donbt. Our impression is that there is a many-celled archesporimn. Following tl
. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 16 mopiPttoloitY of sperjiatopiiytes The first indication of a megasporana'inm is the differentia- tion of a gronp of sj-Kirogenons cells innnediatelv beneath the epidermis. It is not a liypodernial jilate. as in the niicrosporan- ginni, bnt a hypodernial mass of cnsideralile extent. AVhether this gronp represents the archesporiTun, or whether it can be traced hack to a few-celled or even to a one-celled arcliesporinm, is still in donbt. Our impression is that there is a many-celled archesporimn. Following tlie dift'erentiation of sporogenous tissne, the exterior sterile cells begin to divide rajjidly, organ- izing the large sterile apical region of the nncellns. About this there develops a very thick integnnient ^vith a long and narrow micropyle. By means of this development of the exterior sterile tissne the sporogenous tissue becomes deeply placed in the nucellns,. Fig. 13,_/;/â,,â ct/ii/t, si'ctioiuil vu'W ol' ^llâ ^|s ivpivsriitud in Fio-. I'J a]-.].earing alniust at its very base. Tu the tissue nsually one cmtrally -|ila<-ed cell shows its selection for func- tioning by enlarging at the expense of adjacent cells. From its .subsc(|n(Mit liehavior it seems that this eidargino- cell is 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 Coulter, John Merle, 1851-1928; Chamberlain, Charles Joseph, b. 1863. New York, D. Appleton
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Keywords: ., bookauthorcoulterj, bookcentury1900, bookdecade1900, bookyear1901
