iQoi] White — The Genus Wwittleseya. ibi 



DESCRIPTION OF THE SPECIES. 



Whittleseya, Newberry, 1853. 



The genus Whittleseya, established by Newberry^ in 1853, 

 embraces a type of narrowly petiolate leaves, more or less flabelli- 

 form in plan, whose nervation is composed of broad and thick, 

 closely or even densely arranged, fascicles or bands ot nerves 

 originating chiefly from a marginal strand on either side of the 

 base and sometimes forking, not far above the point of origin, 

 before passing upward, longitudinally parallel, to the generally 

 truncate apex, where the nerves of each band or fascicle abruptly 

 converere in a more or less distinct crenulation or tooth. 



The leaves may be oblong, squarrose, triangular, cuneate or 

 linear. They are always narrowed, sometimes so abruptly as to 

 give an almost round-truncate profile, at the base. The petiole 

 is usually long, and oiten filamentose. The lateral borders are in 

 most instances nearly parallel, and the distal border is frequently 

 acutely dentate. In the more cuneate forms the basal marginal 

 nerves are less developed, the nerve fascicles radiating more 

 directly from the summit of the petiole. In some species, and 

 circumstantially in others, the vascular bands coalesce and are so 

 densely arranged in the thick leaf substance as to be hardly separ- 

 able. In most species the thickened central portions of the bands 

 produce low costae, though the bands are not wholly distinct from 

 one another below the teeth ; or, in many examples in which the 

 teeth or corrugations are obscure, they may not be distinguished, 

 unless topographically, for a portion of their length. The bands 

 sometimes divide once near the base. Above the base they con- 

 tinue nearly parallel to the lateral margins of the leaves. Fre- 

 quently the lateral margins are very slightly infolded near the 

 apex. 



The branchlets or possibly the stems of this type, as shown 

 in specimens of Whittleseya microphylla, are slender, rarely divid- 

 ing at a rather wide angle, apparently naked at some distance 

 below the apices, and probably woody as indicated by the rather 

 densely carbonaceous residue. The leaves, still attached to the 



^ Annals of Science, vol, i, No. 10, Cleveland, 185J, p. 116. 



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