142 THE FLORA OF THE DAKOTA GKOUP. 



Order ROSACEA. 

 Tribe POMEyE. 



Crataegus laurenciana, sp. uov. 

 PI. XXXVIII, Fig. 1. 



Leaves large, oliovate, rounded at apex, attenuate at ])a,se into n brondly 

 margined petiole; simply dentate; primary nerve narrow; uppiu- secouda- 

 i-ies ^•ery ol)li(pie, ramose, the loAver gradually more open, nearly at right 

 angles, simple and curved up in the wing of the petiole. 



A beautiful leaf of somewhat thin (not coriaceous) texture, I'i.S"'" long 

 including the long decurring base, T*"" broad in the upper part. The middle 

 secondarie.s, at an angle of 20° to 30° of divergence, are much branched 

 outside in parallel, simple or ramose tertiaries; the lower are simple, grad- 

 ually more open and less distant, becoming camptodroine in the Aving of the 

 petiole where they follow the borders in ai'eoles. The teeth are blunt, .short, 

 simple, slightly turned upward and separated by shallow sinuses. 



This species has, in the fossil plants, an intimate relation with C. untiqna 

 Heer,^ from which it differs in the borders, the nearly round upper part of 

 the le;if, the broad, prolonged, decurrent base nerved in its wdiole length, the 

 shorter, more distant teeth, etc. It may be compared also to C. aria L. var. 

 I'crollana Gaud.- Its nearest affinity is, however, with the leaves of some 

 varieties of the living North American C. tomentofm L., which luive a mar- 

 gined petiole, with the bordering lamina quite as large as in the Cretaceous 

 species and nerved in its whole length. 



Habitat: P^llsworth County, Kansas. No. 750 of the museum of the 

 University of Kansas; E. P. West, collector. 



CRAT.a;GUS TENUINERVIS, Sp. nOV. 



PI. LIV, Figs. 5-7. 



Leaves ol)long-ovate, dentate all around, once lobate at liase, narrowed 

 into a long petioh;; midrib tliin; lateral primaries slightly curved l)ack, 

 l)raiic]iing on both sides, prolonged to the apex of the lobes; secondaries 

 simple or ramose, aljout e(][uidistant, oblique, straight and parallel, ending 

 in the large teeth. 



This species is closely allied to the preceding, especially differing by 

 its thinner texture, the dentate borders, and in being only one, lobed at base. 



' Fl. Fobs. Arct., vol. 1, p. 125, PI. i, Figs. 1, 2. 



'Gaudin et Strozzi, Contrib., pt. 4, p. 26, PI. vii, Figs. 5, 6. 



