Serotinal

Soon, however, the allantois undergoes changes of development looking towards the formation of the placenta at the base of the ovum, where the chorionic villi becomes more and more developed, the serotinal tissue growing toward and around them and encapsulating them, while at the same time the vessels of the serotinal layer become dilated to form the material system of placental blood-supply.

Source: wiktionary

The inner (chorionic) surface [of the placenta] exhibits ramifications of the umbilical vessels, and is closely covered on its fœtal side by the amnion; from its placental (outer, serotinal) side multitudes of arborescent vasculi villi arise[…].

Source: wiktionary

The psoraleas, prairie clovers and blazing stars would probably occur to all us among the most the most abundant of the secondary species in the vernal, estival and serotinal aspects of the prairies respectively.

Source: wiktionary

Whenever societies are well developed, they regularly manifest a fairly definite seasonal sequence, producing what have long been known as aspects[…]. As phenomena of the growing season, these were first distinguished as early spring or prevernal, vernal proper, estival, and serotinal or autumnal, but there may also be a hiemal aspect, especially for animals, in correspondence with an actual and not merely a calendar winter as in California.

Source: wiktionary