sporangium's Usage Examples:

In the megasporangium, on the other hand, the four megaspores, which arise from a single mother-cell, are nourished at the expense of the other sporogenous cells and of the tapetum.

The sporangia of the Psilotaceae are associated in synangia, which occupy the same position relatively to the sporophyll, as the single sporangium of Lycopodium or the group of sporangia in Spenophyllum majus.

The sporangium is of considerable size, and dehisces by a median slit, the annulus being a more or less definitely limited horizontal ring of cells near the apex.

The megaspores, of which there are many in the megasporangium, have a diameter about three times that of the microspores.

At the time of sporangial formation the protoplasm with numerous nuclei streams into the swollen end of the sporangiophore and there becomes cut off by a cell-wall to form the sporangium.

/ s h the elongated horizontal pedicel on which the sporangium is seated corresponds to the short base of a FIG.

The sporangium with its endogenous spores has been compared with an ascus, and on these grounds the group is placed among the Ascomycetes - a very doubtful association.

This mode of sporeformation is totally different from that in the ascus; hence one of the difficulties of the acceptance of Brefeld's view of the homology of ascus and sporangium.

In Mucor, for example, the end of the primary hypha swells into a spheroidal head (sporangium), the protoplasm of which FIG.

In some of the heterosporous forms (Lepidocarpon, Miadesmia) the sporangia were sometimes surrounded by an integument; and since only a single megaspore attained maturity, the structure of the megasporangium suggests a comparison with an ovule.

Short trabeculae of sterile tissue have been found to project into the cavity of the sporangium of some species.

As mentioned before, the connexion between these two groups is very doubtful, and the derivation of the ascus from an ordinary sporangium of the Zygomycetes cannot be accepted.