Definition of pteridosperm in English:

pteridosperm

noun ˈtɛrɪdəʊspəːmtəˈridəˌspərm

A fossil plant which is intermediate between the ferns and seed-bearing plants, dying out in the Triassic period.
Formerly placed in their own taxon (class Pteridospermeae), but now included with the gymnosperms
Also called seed fern
Example sentencesExamples
- The first seeds evolved in a group of vascular plants sometimes called the pteridosperms, or ‘seed ferns.’
- 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.
- Seed-ferns or pteridosperms evolved rapidly in the Carboniferous; the first conifers are known from the Upper Carboniferous.
- In the coal swamps of North America grew pteridosperms like Medullosa, a seed plant that resembles modern tree-ferns, but which bore seeds.

Origin

Early 20th century: from modern Latin pteridospermeae, from Greek pteris, pterid- 'fern'.

Definition of pteridosperm in US English:

pteridosperm

nountəˈridəˌspərm

An extinct plant that is intermediate between the ferns and seed-bearing plants, dying out in the Triassic period.
Formerly placed in their own taxon (class Pteridospermeae), but now included with the gymnosperms
Also called seed fern
Example sentencesExamples
- 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 first seeds evolved in a group of vascular plants sometimes called the pteridosperms, or ‘seed ferns.’
- The Pteridopsida were present, bearing spores on their leaves as they do today, but there were also fernlike seed-bearing ferns, the pteridosperms.
- In the coal swamps of North America grew pteridosperms like Medullosa, a seed plant that resembles modern tree-ferns, but which bore seeds.
- Seed-ferns or pteridosperms evolved rapidly in the Carboniferous; the first conifers are known from the Upper Carboniferous.

Origin

Early 20th century: from modern Latin pteridospermeae, from Greek pteris, pterid- ‘fern’.

单词	pteridosperm
释义	Definition of pteridosperm in English: pteridosperm noun ˈtɛrɪdəʊspəːmtəˈridəˌspərm A fossil plant which is intermediate between the ferns and seed-bearing plants, dying out in the Triassic period. Formerly placed in their own taxon (class Pteridospermeae), but now included with the gymnosperms Also called seed fern Example sentencesExamples The first seeds evolved in a group of vascular plants sometimes called the pteridosperms, or ‘seed ferns.’ 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. Seed-ferns or pteridosperms evolved rapidly in the Carboniferous; the first conifers are known from the Upper Carboniferous. In the coal swamps of North America grew pteridosperms like Medullosa, a seed plant that resembles modern tree-ferns, but which bore seeds. Origin Early 20th century: from modern Latin pteridospermeae, from Greek pteris, pterid- 'fern'. Definition of pteridosperm in US English: pteridosperm nountəˈridəˌspərm An extinct plant that is intermediate between the ferns and seed-bearing plants, dying out in the Triassic period. Formerly placed in their own taxon (class Pteridospermeae), but now included with the gymnosperms Also called seed fern Example sentencesExamples 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 first seeds evolved in a group of vascular plants sometimes called the pteridosperms, or ‘seed ferns.’ The Pteridopsida were present, bearing spores on their leaves as they do today, but there were also fernlike seed-bearing ferns, the pteridosperms. In the coal swamps of North America grew pteridosperms like Medullosa, a seed plant that resembles modern tree-ferns, but which bore seeds. Seed-ferns or pteridosperms evolved rapidly in the Carboniferous; the first conifers are known from the Upper Carboniferous. Origin Early 20th century: from modern Latin pteridospermeae, from Greek pteris, pterid- ‘fern’.
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