452 FOSSIL PLANTS/Gymnosperms widespread in the fossil record of the Mesozoic and Tertiary eras The leaf morphology ranges from highly dissected resembling leaves of Czekanowskiales to forms very similar to those of the modern species (Figure 15) Even though ovules attributable to the Ginkgoales were common in their dispersed form during the Mesozoic very few intact reproductive structures are known Ovulate structures and catkin-like pollen cones have been reported from the Jurassic of Yorkshire, England Peltaspermales (Permian to Late Triassic) The concept of Peltaspermales is based on leaves, pollen organs, and ovulate organs Knowledge of whole plants is scant, but organ associations and characteristic cuticular features have been used to piece together some aspects of whole plant morphology Clusters of pollen sacs and ovule-bearing structures were borne in a pinnate arrangement on branches Plants bore large fern-like leaves, which were probably deciduous This is consistent with a woody habit cuticular features, and the association of pollen with ovules have been used to piece together some aspects of whole plant morphology Woody stems bore fernlike foliage Ovules were borne in cupules, whereas pollen was borne in elongated sacs on the underside of oval laminae Woody stems bore fern-like foliage Caytoniales (Upper Triassic to Lower Cretaceous) This extinct group is widely recognized on the basis of distinctive leaves The leaves (Sagenopteris) are palmate, composed of three to six lanceolate blades attached to a petiole (Figure 16) Each blade has an anastomosing network of veins Knowledge of whole plants is scant, but the concept of the group has been built from well-established organ associations Ovules were borne in cupules along a branch (Caytonia) The pollen was produced in elongated anther-like structures (Caytonanthus) Caytonia is though to have been a small tree with a woody trunk Pentoxylales (? Jurassic to Cretaceous) The concept of this group is based on leaves, pollen organs, and ovulate organs Knowledge of whole plants is scant, but organ associations, characteristic This extinct group is known from India, New Zealand, and Australia Knowledge of whole plants is scant, but the stems (Pentoxylon) are known to have borne a distinctive type of wood, resembling that of conifers The leaves were large (up to 20 cm long), strap-shaped, and borne on short lateral shoots Figure 15 Leaf of the Maidenhair tree, Ginkgo gardneri (Palaeo cene, Isle of Mull, Scotland) Figure 16 The extinct gymnosperm Caytonia bore palmate leaves: Sagenopteris phillipsi (Jurassic, Cayton Bay, Yorkshire, England) Corystospermales (Mid-Triassic to Mid-Jurassic)