| Gymnosperms
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos (γυμνόσπερμος), meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilized state). Their naked condition stands in contrast to the seeds or ovules of flowering plants (angiosperms), which are enclosed during pollination. Gymnosperm seeds develop either on the surface of scale- or leaf-like appendages of cones, or at the end of short stalks (Ginkgo).
The gymnosperms and angiosperms together comprise the spermatophytes or seed plants. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, Gnetales (Gnetophyta, Ephedra and Welwitschia), and Ginkgo (a single living species).
Source: http://en.wikipedia.org/wiki/Gymnosperms
Doliostrobus certus | | | | ČB566 | Doliostrobus certus | | | | ČB567 | Doliostrobus certus | | | | ČB577 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 33, fug. 5 | | | ČB771 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 33, fig. 12 | | | ČB758 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 30, fig. 6 | | | ČB757 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 33, fig. 14 | | | ČB786 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 33, fig. 9 | | | ČB756 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) nevyobrazeno | | | ČB762 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) nevyobrazeno | | | ČB774 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) nevyobrazeno | | | ČB775 | Doliostrobus certus | Bů?ek, Holý, Kvaček (1968) Pl. 32, fig. 7 | | | ČB792 | Doliostrobus certus | AD Bůžek, Holý, Kvaček (1968) | | | ČB793 | Doliostrobus certus | Bůžek, Holý, Kvaček (1968) Pl. 32, fig. 4 | | | ČB755 | Doliostrobus | | | | ČB569 | Doliostrobus | | | | ČB538 | Eusphenopteris nummularia | | | | p4646 | Eusphenopteris nummularia nummularia | Šimůnek (1994), Pl. I, fig. 8, 8a | | | ZŠ43 | Eusphenopteris obtusiloba | | | | ZŠ815 | Eusphenopteris sauveuri | | | | ZŠ605 |
|