As a rule, too, in the prothallus only one of the archegonia shows any further signs of development.
The prothallus is a small underground body destitute of chlorophyll.
In the case of L. inundatum the length of time which elapses between the coming of the prothallus is nothing like so great.
prothallus, the leaf-shaped green organism that grows from the spore of a fern and produces sexual organs, 49.
For a while the newly-born Fern relies upon the prothallus for sustenance, but eventually starts an independent existence.
It is on the prothallus, however, that the sexual organs are produced, and after fertilization the plant as we know it arises.
Upon the prothallus, or somewhat sunken in it, the sexual organs appear.
This filament is the beginning of the body, known as the prothallus, which is responsible for the sex organs.
On the under side of the prothallus two kinds of organs appear (Fig. 510).
In some of the Lycopodiums the spores have a remarkable habit of resting before the development of the prothallus.
Plural prothalli (prō-thāl'ī)
The gametophyte of homosporous ferns and some other plants. Prothalli have chlorophyll for photosynthesis, but they are not differentiated into roots, stems, or leaves. They are usually small, flat, and delicate. Prothalli develop from germinated spores, and they bear both archegonia for producing eggs and antheridia for producing sperm. See more at alternation of generations.