| 释义 |
Definition of seed fern in English: seed fernnoun another term for pteridosperm Example sentencesExamples - One example, from the Calhoun Flora of Illinois, is a seed fern that bears prepollen (a kind of microspore) far bigger than any known wind-dispersed pollen.
- There is some agreement that both living and extinct cycads were derived from seed ferns, but paleobotanists still debate exactly if, when, and how this happened.
- Large plants were dominantly conifers, followed by lesser amounts of cycads, seed ferns, and ginkgos.
- Furthermore, many of these so called ‘preferns’, have been previously - and often equally convincingly - assigned to such varied groups as lycopsids, seed ferns, and intermediates between sphenopsids and ferns.
- Glossopteris, for example, was an extinct seed fern with distinctive leaf patterns.
Definition of seed fern in US English: seed fernnoun another term for pteridosperm Example sentencesExamples - Glossopteris, for example, was an extinct seed fern with distinctive leaf patterns.
- There is some agreement that both living and extinct cycads were derived from seed ferns, but paleobotanists still debate exactly if, when, and how this happened.
- Furthermore, many of these so called ‘preferns’, have been previously - and often equally convincingly - assigned to such varied groups as lycopsids, seed ferns, and intermediates between sphenopsids and ferns.
- One example, from the Calhoun Flora of Illinois, is a seed fern that bears prepollen (a kind of microspore) far bigger than any known wind-dispersed pollen.
- Large plants were dominantly conifers, followed by lesser amounts of cycads, seed ferns, and ginkgos.
|