46 CONTRIBUTIONS TO PAL^ONTOLOGY 



So few specimens of Cretaceous or Tertiary representatives of Typha have been described or 

 identified specifically that there is nothing to be gained in describing the Medicine Bow specimens 

 as a new species. From the environmental point of view, however, the presence of this common 

 type of aquatic monocotyledon is of significance. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 372. 



Colledion—V. C. Mus. Pal., No. 1297. 



Family PANDANACE^ 



Genus PANDANITES Dorf, n. gen. 



This generic name is proposed for specimens with the characteristics of the following type 

 species. The name is derived from the family Pandanacese, whose members posscss spirally 

 arranged Unear leaves which are leathery, keeled, and mostly spinulose on the margins and keel.^ 



Pandanites corsoni Dorf, n. sp. 

 (Plate 3, Fig. 4) 



Only the single specimen figured was encountered in the collections. I •was at first inclined 

 to regard this as the impression of a portion of a palm leaf . After careful study of all the available 

 living and herbarium specimens of palms at The New York Botanical Garden, I was convinced 

 that none of these was comparable to the fossil. It soon became apparent that its characters were 

 very similar to those of the PandanaceiE. 



Description — Leaf of unknown lengt-h, width 5 cm., texture evidently leathery; prominent 

 central keel, and each half of leaf marked by a subsidiary central dorsal keel ; leaf surface marked 

 by 40 to 46 longitudinal, parallel veins which are irregularly connected by transverse veinlets 

 which niay be perpendicular or obhque to the veins; margins of leaf invested with strongly spinose 

 teeth about 5 to 6 mm. apart. 



The usual description of the leaves of the Pandanaceie emphasizes that both the leaf edges 

 and the central keel are spinulose. In Uving specimens of Pandanus, however, I have noticed 

 that the keel is perfectly smooth in the basal half of the leaves, becoming spinulose only in the 

 distal half . The absence of teeth, therefore, in the fossil specimen is not considered of taxonomic 

 importance. It is doubtful, moreover, whether spines along the keel would be discernible in a flat 

 fossil impression. 



The modern PandanacetB are represented in the tropics and subtropics of the Old World by 

 three genera: Sararanga Hemsl. (Solomon Islands) ; Freycinetia Gaudich (East Indies to Australia 

 and New Zealand) ; and Pandanus Linne (Asia and Af rica) . They are usually f ound in lowland 

 marshes or along sea-coasts and are not known to occur under typically temperate conditions. 



There are no fossil specimens known to me which are comparable to Pandanites corsoni. 

 There is a superficial resemblauce in Bactrites pandanifolius Berry from the Eocene Lisbon forma- 

 tion of Mississippi.^ This, however, is typically a flat leaf, with a single prominent midrib and 

 longer teeth. 



This species is named for Mr. Andrew Corson, who was instrumental in the original dis- 

 covery of fossil leaves on his property. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 372. 



Collection—V. C. Mus. Pal., Holotype No. 1298. 



Family CYPERACE^ 



Genus CYPERACITES Schimper 



Cyperacites sp. 



(Plate 1, Fig. 11) 



There are a number of specimens in the collections which are quite obviously monocotyle- 

 donous leaves with venation characters unlike those referred to Typha. As shown in the figured 

 specimen they are long, 8 to 12 mm. wide, and provided with numerous fine, parallel veins about 



■ Hutchinson, J.. The Families of Flowcring Planta, vol. II, 159, 1934. 

 2 Berry, E. W., U. S. Geol. Surv. Prof. Paper 92, 52, pl. 7, figa. 1-6, 1924. 



