How to use Sporogonium in a sentence
The sporogonium of the liverworts is in the simpler forms simply a spore-capstile with arrangements for the development, protection and distribution of the spores.
The hydrom strand has in most cases no connection with the leaves, but runs straight up the stem and spreads out below the sexual organs or the foot of the sporogonium.
In the stalk of the sporogonium there is a similar strand, which is of course not in direct connection with, but continues the conduction of water from, the strand of the gametophytic axis.
The central hydrom strand in the seta of the sporogonium of most mosses has already been alluded to.
Thus the histological differentiation of the sporogonium of the higher mosses is one of considerable complexity; but there is here even less reason to suppose that these tissues have any homology (phylogenetic community of origin) with the similar ones met with in the higher plants.Advertisement
The structure of the stomata of the sporophyte of vascular plants is fundamentally the same as that of the stomata on the sporogonium of the true mosses and of the liverwort A nihoceros.
There is here obviously a certain parallelism with the case of Bryophyta, where the sporogonium arising from the oospore is epiphytic and partially parasitic upon the female plant, and always culminates in the production of spores.
Not even Riccia, with its rudimentary sporogonium, has so simple a corresponding stage as Bangia, for, while there is some amount of sterile tissue in Riccia, in Bangia the oospore completely divides to form carpospores.
It may be regarded as derived from a wholly dependent sporogonium not unlike that of some of the simpler Bryophyta; the latter are assumed to have arisen from primitive Algal forms, in which, as the first step in the interpolation of the second generation in the life cycle, the fertilized ovum gave rise to a group of swarm spores, each of which developed into a new sexual plant.
If the axis of such a sporogonium were prolonged downwards into the soil to form a fixing and absorptive root, the whole structure would become a physiologically independent plant, exhibiting in many though by no means all respects the leading features of the sporophyte or ordinary vegetative and spore-bearing individual in Ptericlophytes and Phanerogams. These facts, among others, have led to the theory, plausible in some respects, of the origin of this sporophyte by descent from an Anthoceros-like sporogonium (see PTERIDOPHYTA).Advertisement
Similar differentiation, differing in some details, takes place independently in the other generation, the sporogonium.