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 1 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 Voltzia. The strobili, referred by Heer to three species, do not 

 exhibit any well-marked specific differences ; the longest example, 

 L. crassipes, is 7cm. 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 V. 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 2 includes in Leptostrobus clusters of long 

 linear leaves apparently borne on short shoots and resembling the 

 needles of 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 3 . It 

 would be difficult to draw any 

 generic distinction between Lepto- 

 strobus and Voltzia especially F. 

 keuperiana. 



SWEDENBORGIA. Nathorst. 



This genus 4 is founded on lax 



oval strobili bearing small cone- 



scales with long Stalks and a FIG. 749. Swedenborgia cryptomerides. 

 Single seed (fig. 749, B). In the A, Strobilus. B, Fertile leaf. (After 



., Nathorst; nat. size.) 



type-species, S. cryptomerides, the 



cones reach 7 cm. in length and the scales are divided distally 



into 4 or 5 acute digitate lobes. Nathorst compares the strobili 



1 Schenk (68) Pis. vn. et seq. 2 Heer (82) p. 23, Pis. vn., vm. 



3 Ibid. (77) ii. PL xm. fig. 14. 4 Nathorst (78) B. p. 30, PI. xvi. 



