34 THE FLOltA OF THE DAKOTA GEOUP. 



Habitat: Seven miles north of Glascoe, Kansas. No. 511 of the Mu- 

 seum of Comparative Zoology of Cambridge, Massachusetts. 



Tribe TAXE^^. 



Phyllocladus subintegkifolius Lesq. 

 PI. II, Pigs. 1, 2, 3. 



Cret. FL, p. 54, PI. i. Fig. 12. Thinnfeldia Lesquereuxiana Heer, Fl. Foss. Arct., 

 vol. 6, 2 Abth., p. 37, PI. xliv. Figs. 9, 10; PI. xlvi, Figs. 1-12. 



Leaves coriaceous, oblong, tapering doAvnward to a short petiole, ob- 

 tuse at apex, obtusely dentate above; midrib narrow, half round, slightly 

 defined in the small leaves, distinct up to near the apex in the larger ones, 

 and of the same thickness as the petiole ; lateral nerves close, more distinct, 

 of equal size and equidistant in the small leaves, irregular in size and dis- 

 tance in the larger, here and there inflated and more prominent; angle of 

 divergence 20°. 



The leaves, as far as I have seen them, vary from 3"'" to 12"" in length, 

 and from l*"" to 3"" in width in the middle or above, being there either un- 

 dulate or obtusely dentate ; the lateral nerves are obscurely defined, and are 

 either simple or forking at a very acute angle of divergence, the divisions 

 reaching the borders. 



The genus Thinnfeldia Ett., to which Heer has referred leaves of 

 apparently the same kind as the one described in Cret. Fl. (loc. cit.), is 

 characterized by its author as follows: "Fronds pinnatifid ; pimife or 

 leaflets oblong, ovate-lanceolate, oblong-ovate, decurrent, confluent, cori- 

 aceous ; primary nerves vanishing below the apex, divided into dichotomous 

 nervilles, all the branches reaching the borders." Schimper remarks on the 

 genus that the likeness of the fronds and leafy branches to those of the genus 

 Phyllocladus has induced Ettingshausen to place these plants with the 

 conifers. On the other hand Scheldt considers them as Cycadese, while F. 

 Braun has referred them to the ferns. This last opinion is admitted by 

 Schimjjer, and judging from the species which I have been able to see 

 figured (Th'onifcItJia rhomboklaUs Ett.,* T.salirjna Schenk,^ T. rotundata Nath.,* 

 T. Nordenskwldl Natli.*) this opinion is e\ddently authorized. For in all 

 these species the leaflets are decurrent or confluent, the median nerve is 

 either in distinct or not seen at all, the lateral ones diverging at a far more 

 open angle of divei'gence, distinctly forking once or twice. Nothing like 



' Schimper, Pal. Vdg., Atljts, PI. xi-V, Fig. 1. ^Nathorst, Fl. vid. Bjuf., pt. 1, PI. I, Figs. 5, 6. 



= Loo. cit., Figs. 9-12. ••Pfl. Patsjo, PI. Vl, Figs. 4, 5. 



