Maeyland Geological Survey 431 



Subfamily TAXODIEAE 



Genus SPHENOLEPIS Schenk 

 [Palseontograph ica, Band xix, 1871, p. 243] 



The generic name 8phe7iolepidnim was proposed by Heer as a substi- 

 tute for 8phenolepis Schenk (1871) as the latter had been previously- 

 used in the animal kingdom. In his treatment of these plants in Zittel's 

 Handbuch Schenk adopts Heer's generic name which had meanwhile 

 come into general use. As however, all modern nomenclatorial codes, 

 both zoological and botanical, do not regard the use of a name in the 

 one kingdom as prohibiting its use in the other we must return to 

 Schenk's original usage. 



Sphenolepis may be defined as follows : Branches and twigs alternate. 

 Phyllotaxy spiral. Leaves decurrent, more or less imbricated, acute, 

 more or less appressed, especially on the older branches. Cones small, 

 oblong or spherical, borne on short lateral branches. Cone-scales per- 

 sistent, leathery, somewhat divergent at maturity, in habit suggesting 

 Sequoia. The number and position of the seeds is altogether uncertain. 



Although Solms-Laubach considers ^ that these forms cannot be pre- 

 cisely located in any of the existing subfamilies of Conifers most authors 

 refer them to the Taxodiese comparing them with the existing species 

 of Sequoia and Arthrotaxis, especially the latter, with which as regards 

 the cones the leaf form and arrangement and the general habit there is 

 the closest similarity, amounting almost to an actual demonstration of 

 relationship. 



The genus appears in beds of Ehsetic age both in Europe and South 

 America. In North America one species has been recorded from the 

 Oregon Jurassic, and Saporta has described a species from the Upper 

 Jurassic of Portugal. Species of this genus are widespread and char- 

 acteristic of the Wealden and Lower Cretaceous and constitute a very 

 abundant element in the flora of the Potomac Group, where they are 

 represented by remains of both foliage and cones. As has been frequently 

 pointed out the genus may be composite since the difliculty of separation 



^ Solms-Laubach, Fossil Botany, 1891, p. 71. 



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