C, longitudinal section of a spike, with a single macrosporangium at the base; the others, microsporangia, × 3.

Secondly, the nucleus of the ovule corresponds with the macrosporangium of Selaginella, through the connecting link of the conifers, where the ovule is of similar origen and position to the macrosporangium of the Lycopodiaceæ.

The macrosporangia are also ordinarily known as “ovules,” a name given before it was known that these were the same as the macrosporangia of the higher pteridophytes.

The spores are of two kinds, as in Selaginella, but the macrosporangia contain numerous macrospores.

In the seed plants the macrosporangia remain attached to the parent plant, in nearly all cases, until the archegonia are fertilized and the embryo plant formed.