. Fossil plants : for students of botany and geology . Paleobotany. XLV] voltzia; swedenborgia 295 phylls. The species Voltzia recubariensis (Mass.) represented by several vegetative shoots, imperfect cones, cone-scales, and seeds in the Muschelkalk beds of Recoaro^ illustrates the impossibility in the case of sterile specimens of drawing any satisfactory line between Voltzia and Pagiophyllum. Heer instituted the genus Leptostrobus for strobili from Jurassic strata in Siberia agreeing closely in habit and in the form of the megasporophylls with those of VoUzia. The strobili, referred by Heer t
. Fossil plants : for students of botany and geology . Paleobotany. XLV] voltzia; swedenborgia 295 phylls. The species Voltzia recubariensis (Mass.) represented by several vegetative shoots, imperfect cones, cone-scales, and seeds in the Muschelkalk beds of Recoaro^ illustrates the impossibility in the case of sterile specimens of drawing any satisfactory line between Voltzia and Pagiophyllum. Heer instituted the genus Leptostrobus for strobili from Jurassic strata in Siberia agreeing closely in habit and in the form of the megasporophylls with those of VoUzia. The strobili, referred by Heer to three species, do not exhibit any well-marked specific differences; the longest example, L. crassipes, is 7 cm. in length and 1-5 cm. broad: the scales, 7—8 mm. broad, are entire at the distal margin or more or less lobed and in some specimens the scales are hardly distinguishable from those of F. heterophylla. Heer states that two-winged seeds are borne on some of the scales though the evidence is not clear. In a later account Heer^ includes in Leptostrobus clusters of long linear leaves apparently borne on short shoots and resembling the needles oi Pityites Solmsi Sew., Schizolepis Braunii, and Jeffrey's Prepinus. These leaves, described as L. rigida and L. angusti- folia, though in close association with strobili are not actually connected with them; they differ considerably from the short, triangular, imbricate leaves shown in one of Heer's figures imme- diately below the fertile portion of an axis of L. crassipes^. It would be difficult to draw any generic distinction between Lepto- strobus and Voltzia especially V. heuperiana. SWEDENBORGIA. Nathorst. This genus * is founded on lax oval strobili bearing small cone- /^ scales with long stalks and a Fio. 749. Swedenborgia cryptomerides. single seed (fig. 749, B). In the A,Strobilus. B, Fertile leaf. (After ° . rf -J 1 Nathorst; nat. size.) type-species, S. cryptomerides, the cones reach 7 cm. in length and the scales ar
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