. Fossil plants : for students of botany and geology . Paleobotany. 52 GINKGOALBS [CH. the axis is 2-3 cm. long and some microsporangia are seen in their original position, while others are detached^. It is by no means unlikely that these specimens are portions of male flowers of GinJcgoites digitata or of some other species, but this cannot be definitely settled until better material is available. Some Rhaetic fossils described by Nathorst^ as Antholithus Zeilleri present a certain resemblance to these supposed male flowers. One of. Fig. 654. Antholithus sp. (Sedgwick Museum, Fig. 655. Anthol
. Fossil plants : for students of botany and geology . Paleobotany. 52 GINKGOALBS [CH. the axis is 2-3 cm. long and some microsporangia are seen in their original position, while others are detached^. It is by no means unlikely that these specimens are portions of male flowers of GinJcgoites digitata or of some other species, but this cannot be definitely settled until better material is available. Some Rhaetic fossils described by Nathorst^ as Antholithus Zeilleri present a certain resemblance to these supposed male flowers. One of. Fig. 654. Antholithus sp. (Sedgwick Museum, Fig. 655. Antholithun Zeilleri. Cambridge; A,ca. X U; B,ca. X 2.) A, drawn (After Nathorst; x2f.) by M. Seward; B, drawn by L. D. Sayers. Nathorst's specimens from Scania is reproduced in fig. 655 twice natural size; the photograph, for which I am indebted to Prof. Nathorst who published it in 1908, shows a cuticular preparation of the axis and microsporangia. The axis of Antholithus is dichotomously branched and bears terminal clusters of micro- sporangia about 3-5 mm. long, usually eight in a cluster; several of them have dehisced longitudinally and the apices show a slight separation of the two halves. In some of the sporangia Nathorst found microspores with an average length of 40—43/x agreeing closely with the spores of Ginkgo and recent Cycads. Nathorst considered that Antholithus Zeilleri may be a male flower of some Ginkgoaceous plant though a correlation with a Cycadean bype is by no means excluded. There is, however, a general resemblance between the EngHsh Jurassic specimens shown in fig. 654 and the Rhaetic species; the latter is distinguished by a greater tendency ^ Seward and Gowan (00) B. PI. ix. fig. 28. 2 Nathorst (08) p. 20, PI. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Seward, A. C. (Albert C
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