The first formed portion of the stern in all species of Selaginella which have been investigated possesses an exarch haplostele.
In Selaginellites Suissei there was a definite strobilus bearing both microand megasporangia; in each of the latter from 16 to 24 megaspores were contained; in Selaginellites primaevus, however, the number of megaspores was only 4, and the resemblance to a recent Selaginella was thus complete.
The country in general is a fern paradise, and the iridescent creeping Selaginella (akin to Lycopodium) festoons the undergrowth by the wayside.
Some analogy among recent Lycopods is afforded by the stem of Isoetes, and by the base of the stem in Selaginella spinosa; in the fossils the process was of a more normal type, but some of its details need further investigation.
The primary structure of the stem was thus of a simple Lycopodiaceous type, resembling on a larger scale what we find in the upright stem of Selaginella spinosa.
Thus the position of the root in Selaginella is different from what obtains in the other Vascular Cryptogams. A point of interest in this heterosporous genus is that the formation of the prothallus may commence before the megaspore is liberated from the sporangium.
Each leaf bears a ligule resembling that of Selaginella in structure and position.