pteridosperm

How To Use pteridosperm In A Sentence

• 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 pollen organs are synangia, each consisting of a ring of microsporangia united at their bases around a hollow center, a common feature among so called pteridosperms.
• 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.