FLORA OF THE WOODBINE SAND AT ARTHURS BLUFF, TEX. 



169 



FanUly ANACARDIACEAE. 



Genus RHUS Liune. 



Rhus redditiformis Berry. 



Plate XXXVII, fig. 2. 



Rhus redditiformis Berry, Torrey Bot. Cluli Bull., vol. 

 3!», p. 397, pi. 31, fig. 2, 1912. 



Leaves compound, probably trilobate. Leaf- 

 lets petiolate, ovate, with bluntly pointed tips- 

 cuneate bases, and entire or undulate margins 

 forming a few distal shallow, broadly roimded 

 lobules separated by broad, shallow sinuses. 

 Terminal leaflet nearly equilateral, about one, 

 third larger than the lateral leaflets, about 4 

 centimeters in length by 2 centimeters in 

 maximum width, which is about midway 

 between the apex and the base; petiole 5 

 millimeters long; midrib stout, prominent; 

 secondaries thin, five or six alternate pairs, 

 branching from the midrib at angles of about 

 50°, curving slightly upward, anastomosing 

 close to the entire margin. Lateral leaflets 

 inequilateral, the outer limb of the lamina 

 being sUghtly wider and fuller than the iimer 

 limb ; petioles shorter than that of the terminal 

 leaflet, 2 to 3 millimeters in length, diverging 

 from the latter at angles of about 70°; in 

 outline and venation similar to the terminal 

 leaflet, but smaller and showing a tendency 

 to develop slight irregularities 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. .Several Creta- 

 ceous species of Rhus have been described from 

 specimens found in beds as old as the Wood- 

 bine, the Dakota sandstone of Kansas havmg 

 furnished tlu-ee supposed species with pinnate 

 leaves, one of which, Rhus uddeni Lesquereux,*'' 

 was erroneously reported by Ward from the 

 Cheyemie sandstone at Belvidere, Kans. The 

 Cheyenne form proves to be a species of 

 Sapindopsis, and this may also be the botanic 

 afHnity of the type material of Rhus uddeni. 



A small-toothed species from the Cenomanian 

 sandstone of Bohemia has been described by 

 Velenovsky ^" as Rhus cretacea, although tiiis 



2' Saporta, Gaston de, Etudes sur la vSgi5tation du sud-est de la Franco 

 h Ti^poque tertiaire, tome 1, p. 124, pi. 13, figs. 2, a, b, 1S62. 



^ LesquereiLX, Leo, IT. S. Geol. Survey Men. 17, p. 154, pi. 57, flg. 2, 

 1892. 



'" Velenovsky, Josef, Die Flora der Ixilimisclie Kreideformatiou, pt. 4, 

 p. 7, pi. 4, figs. 7-12, 18S5. 



32333°— 22 14 



name was already in use for a very different 

 Cretaceous species described by Heer ^' from 

 material obtained in the Senonian at Quedlin- 

 burg, in Saxony, and recorded by Holhck^' 

 from the Upper Cretaceous of Long Island. 

 The Woodbine species is reathly distinguishable 

 from all the foregoing and adds a well-marked 

 and probably trifoliate CVetaceous form to this 

 genus, which was so largely developed during 

 Tertiary time. In the existing flora Rhus is a 

 prominent element with more than 150 species, 

 most of which are natives of warm temperate 

 and tropical regions. 



A. modern species with ahnost identical foli- 

 age is the South Mrican Rhus villosa Liune. 



Order RHAMNALES. 



Family RHAMNACEAE. 



Genus RHAMNUS Linne. 



Rhamnus tenax Lesquereux. 



Plate XL, figure 7. 



Rhamnus tenax Lesquereux. Am. .lour. Sci., 2d ser., vol. 46, 



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



4, 1874; The flora of the Dakota group, p. 170, pi. 38, 



fig. 6, 1892. 

 Engelhardt, Naturwiss. Gesell. Isis in Dresden Abh. 



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

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



181, 1896. 

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



U. S. Geol. Siurey Prof. Paper 112. p. 114. pi. 25, 



figs. 1, 2, 1919. 



Leaves ovate-lanceolate, acimiinatc, slightly 

 equilateral. Length about 8 centimeters; 

 maximum width about 2 centuneters in the 

 lower hah 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 Alabama. Margins entire, curving in- 

 ward somewhat abruptly to the petiole, which 

 is stout, more or less ciu-ved, and a])out 1 centi- 

 meter or slightly more ui length. Midrib stout, 

 curved, becoming thin in the acuminate tip. 

 Secondaries numerous, thin, approximately 

 parallel, 12 to 14 subopposite to alternate pairs, 

 branching from the midrib at angles of about 

 45^ to 50°, curving slightly upward, campto- 

 drome. 



This species, which was described many 

 years ago by Lesquereux from material col- 



^ Heer, Oswald, Zur Kreideflora von Quedlinburg, p. 14, pi. '3, flg. 11, 

 1S72. 

 » Hollick, Arthur, U. S. Geol. Survey Mon. 50, p. 87, pi. 33, fig.2,lB07 



