FLORA OF THE WdOHDIXE SAXI) AT AHTIITRS BLl'FF. TKX. 



1()9 



Family ANACARDIACEAE 



Genus RHUS Limit. 



Rhus redditiformis Berry. 



Plate XX XVII, fig. 2. 



Rhus redditiformis Berry, Torrey Hut. I'luli Bull., vol. 

 39, p. 397, pi. 31, fig. 2, 1912. 



Leaves compound. proVmhly trilobate. I..eaf- 

 lets petiolate, ovate, witli Mimtly pointed tips- 

 cuneate bases, imd entire or undulate margins 

 forming a few distal shallow, broadly rounded 

 lobules separated by broad, shallow sinuses. 

 Terminal leaflet nearly equilateral, about one, 

 third larger than the latend leaflets, about 4 

 centimeters in length by 2 centimeters in 

 maximum width, which is about midway 

 between the apex and the base: petiole r> 

 millimeters long; midrib stout, prominent; 

 secondaries thin, five or six alternate pairs, 

 branching from the midrib at tingles of about 

 50°, curving slightly upwai-d. anastomosing 

 close to the entire margin. Lateral letiflets 

 inequilateral, the outer limb of the lamina 

 being slightly wider and fuller than the inner 

 limb; petioles shorter than that of the terminal 

 leaflet, 2 to 3 milhmeters in length, diverging 

 from the latter at angles of about 70°; in 

 outline and venation similar to the terminal 

 leaflet, but smtiller and shownng a tendency 

 to develop slight iiTeguhxrities in the margin, 

 especially toward their tips. 



This species was named from its rather 

 striking resemblance to the European early 

 Tertiary species Rhus reddita Saporta,^' from 

 Aix, in southeastern France. Severtd Creta- 

 ceous species of lUuift have been described from 

 specimens found in beds as old as the Wood- 

 bine, the Dakota sandstone of Kansas having 

 furnished three supposed species with pinnate 

 leaves, one of which, Rhus uddeni Les(|uereux,'" 

 was erroneously reported by Ward from the 

 Cheyeiuie stmdstone at Belvidere, Ktuxs. The 

 Cheyenne form proves to be a species of 

 Saplndopsif<, and this mtiy ttlso be the botanic 

 affinity of the type materitd of Khvs uddeni. 



A smaU-toothed species from the Cenoniiinian 

 sandstone of Bohemia has been described by 

 Velenovsky ^" :is Rhus cretacM, although tliis 



" Saporta, Gaston de, fitudes sur la vi5g^tatioii (lu sud-est de la France 

 k I'epoque tertiaire, tome 1, p. 124, pi. 13, figs. 2, a, b, 1862. 



^ Lesquereux, Leo, U. S. Geol. Survey Mon. 17, p. I.M, pi. -i", fiR. 2, 

 1892. 



» Velenovsky, Josef, Die Flora der IxJhini.scJie Kreideformation, pt. 4, 

 p. 7, pi. 4, flgs.7-12, 1885. 



name was idready in use for a very difTerent 

 Cretiueous species descril)ed by lleer^' from 

 material obtained in the Senonian at Quedlin- 

 burg, in Saxony, and recorded by Iliillick^'* 

 from the Upper Cretaceous of Long Island. 

 The Woodbine species is readily distinguishable 

 from all the foregoing and adds a well-marked 

 and probalily trifoliate Cretaceous form to this 

 genus, wliich was so largely developed during 

 Tertiary time. In the existing (lora Rhy.>< is a 

 prominent element witli more tliaii l.'iO species, 

 most of which are natives of warm temperate 

 and tropical regions. 



A modern species \vith abnost identical foli- 

 age is the South African Rhus villosa Linn6. 



Order RHAMNALES. 



Family RHAMNACEAE. 



Genus RHAMNUS Llnnfi. 



Rhamnus tenax Lesquereux. 



riate XL, figure 7. 



Rhamnu3 tenax Lesquereux, Am. Jour. Sci., 2d8er.. vol. 46. 



p. 101, 1868; The Cretaceous flora, p. 109. pi. 21, (ig. 



•!. 1874; The flora of the Dakotii group, p. 170, pi. 38, 



fig. 6. 1892. 

 Engelhardt, Naturwiss. Geaell. I.sis in Dre.sden Al>h. 



7, Jahrg. 1891. p. 101, 1892. 

 Bartsch. Iowa Univ. Lab. Nat. Hist. Bull., vol. 3. p. 



181. 1896. 

 Berry, Torrey Bot. Clul) Bull., vol. 39. p. 398, 1912; 



U. S. Geol. Sur\ey Prof. Paper 112. p. 114. pi. 2.5. 



figs. 1, 2, 1919. 



Leaves ovate-lanceolate, acuminate, slightly 

 etjuilateral. Length about 8 centimeters; 

 maximimi width about 2 centimeters in the 

 lower half of the leaf. The dimensions of these 

 leaves are remarkably uniform in all the speci- 

 mens from the Dakota sandstone of the West, 

 as well as in those from the Tuscaloosa forma- 

 tion in -Vlabama. Margins entire, curving in- 

 ward somewhat abruptly to the petiole, which 

 is stout, more or less curved, and about 1 centi- 

 meter or slightly more in length. Midrib stout, 

 curved, becoming thin in the acuminate tip. 

 Secondaries numerous, thin, appro.ximately 

 parallel, 12 to 14 subopposite to alternate pairs, 

 branching from the midrib at angles of about 

 4.5° to 50°, curving slightly upward, campto- 

 drome. 



This species, which was described many 

 years ago by Lesquereux from material col- 



" Heer, Oswald, Ziir Kreideflora von Qiiedlinburg, p. 14, pi. 3, fig. 11. 

 IS72. 

 » HoUick, Arthur, U. S. Geol. Survey Mon. 50, p. S7, pi. 33, flg. 2,1907 



