释义 |
pteridosperm /ˈtɛrɪdəʊspəːm /nounA fossil plant which is intermediate between the ferns and seed-bearing plants, dying out in the Triassic period. Also called seed fern.- Formerly placed in their own taxon (class Pteridospermeae), but now included with the gymnosperms.
The idea that cycads stem from Carboniferous so-called pteridosperms (‘seed ferns’ or seed plants with fern-like foliage) has long been popular with paleobotanists....- The Pteridopsida were present, bearing spores on their leaves as they do today, but there were also fernlike seed-bearing ferns, the pteridosperms.
- The first seeds evolved in a group of vascular plants sometimes called the pteridosperms, or ‘seed ferns.’
OriginEarly 20th century: from modern Latin pteridospermeae, from Greek pteris, pterid- 'fern'. |