differs from other studied species of the genus in having smaller supratectal microechini.
This is not an indication of a security issue such as a virus or attack.
It is suspected that the extension was involved in anemophilous pollination.
Runcaria sheds new light on the sequence of character acquisition leading to the seed.
The living spermatophytes form five groups: In addition to the taxa listed above, the fossil record contains evidence of many extinct taxa of seed plants.
The so-called "seed ferns" (Pteridospermae) were one of the earliest successful groups of land plants, and forests dominated by seed ferns were prevalent in the late Paleozoic.