SAGENOPTERIS 129 



Lateral veins very regular and numerous. No sign of branching. 

 Cf. Oleandridium JEurychoron, Schenk, Palaeontographica, vol. xxxi. 

 1885, p. 168, pi. xiii. figs. 3-5 and pi. xv. fig. 2. Ecclesbourne. 



Ruford Coll. 



V. 2383. Fragment showing the same type of venation. Fair- 

 light. Rufford Coll. 



Genus SAGENOPTERIS, Presl. 



[Sternberg, Flora der Vorwelt, vii. 1838, p. 164.] 



The genus is thus defined in Steinberg's Flora : 



" Frons pinnata, pinnis ternatim rarius binatim compositis. 

 Vense tenuissimae, ramosissimae, aequales, in maculas irregulariter 

 hexagonoides elongatas confluentes. Costse crassse usque ad apicem 

 pinnularum excurrentes." 



Schimper l speaks of Sagenopteris as having no analogue among 

 living plants, but notes the obvious resemblance to Marsilea ; this, 

 however, he does not regard as evidence of natural affinity. 

 Stomata have been found on the lower surface of Sagenopteris, 

 but, according to Schimper, there are none on the lower surface 

 of Marsilea leaves. 



This argument is dismissed by Kathorst, who has observed 

 stomata in the lower epidermal layer of Marsilea ; but the fructi- 

 fication of Sagenopteris has been adduced as stronger evidence than 

 the mere external resemblance in the leaves of the two plants. The 

 so-called sporocarps are described by Nathorst 2 as abundant in the 

 Rhaetic beds near Palsjo ; they cannot be referred to Conifers or 

 Cycads, and, in the absence of Angiosperms, Nathorst is driven to 

 regard them as the fructification of a Marsileaceous plant, and, 

 therefore, of Sagenopteris, as the only genus that can be included 

 in the Marsileacece. The same conclusion was independently 

 arrived at by Heer after examining the Swedish specimens. 3 



1 Trait, pal. veg. vol. i. p. 640. 

 8 Foss. Fl. Schwedens, p. 18. 

 3 Nathorst, loc. cit. p. 18. 



