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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
Cordaites kladnoensis?imůnek a Haldovský (2015), Pl.1, fig.H ZŠ358
Cordaites kladnoensisŠimůnek (1998), fig. 22 ZŠ204
Cordaites kladnoensisŠimůnek (1998), fig. 20 ZŠ243
Cordaites kladnoensisŠimůnek (1998), fig. 27 ZŠ244
Cordaites latus Šimůnek, 1998Šimůnek (1998), fig. 31-32 ZŠ238
Cordaites latus Šimůnek, 1998Šimůnek (1998), fig. 31-32 ZŠ245
Cordaites latus Šimůnek, 1998AD, Šimůnek (1998), 58-61 ZŠ206
Cordaites lubnensisŠimůnek (1998), fig. 34 ZŠ205
Cordaites melnicensisŠimůnek (1988), fig. 71-72 ZŠ241
Cordaites odolovensisAD, Šimůnek (2007) ZŠ237
Cordaites polynervusŠimůnek (1998), fig. 31-32 ZŠ247
Cordaites principalisŠimůnek (1994), Pl. VI, fig. 1 ZŠ59
Cordaites principalisŠimůnek (1994), Pl. III, fig. 8 ZŠ56
Cordaites principalis ZŠ214
Cordaites principalisŠimůnek (1994), Pl. V, fig. 1 ZŠ58
Cordaites principalisfoto ZŠ212
Cordaites principalis ZŠ213
Cordaites principalis ZŠ49
Cordaites principalisŠimůnek (1994), Pl. IV, fig. 1 ZŠ57
Cordaites radvanicensisAD, Šimůnek (1998) ZŠ234
Virtual museum of the Czech Geological Survey, www.geology.cz, (C) Czech Geological Survey, 2011, v.0.99 [13.12.2011]