The enigmatic Triassic ovulate reproductive structures of Dordrechtites are recurved cupules fundamentally comparable to the cupules of Doylea and similar plants.

ABSTRACT

Recent paleobotanical discoveries have renewed interest in the distinctively recurved, seed-bearing cupules of Mesozoic plants, which are important for understanding seed plant phylogeny and the origin of the second integument of the angiosperm ovule. Reanalysis of the enigmatic seed-bearing organ Dordrechtites elongatus from the Triassic of South Africa, the type species of the genus, combined with information from similar material from Antarctica, Argentina and Australia, indicates that Dordrechtites is a highly modified lateral branch of a seed cone. Short lateral projections from a primary cone axis each bear several Dordrechtites units. Each unit consists of a long stalk bearing a straight to sometimes recurved cupule with a long distal extension beyond the cupule apex. Each cupule is flattened in a plane perpendicular to the stalk and distal projection and contains up to two seeds. Structural similarities between Dordrechtites and the cupules of Doyleales indicate that they are homologous, providing new evidence for a close relationship. The persistent cupule stalk and apical extension of Dordrechtites, combined with the flattened cupule, suggests modification for wind and water dispersal.