no. 1760. FOSSIL PLANTS OF THE POTOMAC GROl P -BERRY. 041 



SAPINDOPSIS VARIABILIS Fontaine emend. 



Sapindopsis variabilis Fontaine, Monogr. U. S. Geol. Surv., No. L5, L890, p. 298, 

 pi. 151, fig. 1; pi. 152, figs. 1, 4; pi. L53, fig. 3; pi. 154, figs. 2 4; pi. L55, 

 figs. 2-5.— Fontaine, in Ward, 19th Ami. Rept. U. S. Geol. Surv., IS!)!), 

 pt. 2, p. 690, pi. 1(50, fig. 9; Monogr. U. 8. Geol. Surv., No. 48, L905, pp. 181, 

 482, 489, 532, pi. 114, fig. 2. 



Sapindopsis parvifolia Fontaine, Monogr. I. S. Geol. Surv., No. L5, L890, p. 300, 

 pi. 154, fig. ti. 



Description. — Leaves odd pinnate, sometimes abruptly pinnate, 

 with three pairs of lateral leaflets, which may be opposite, nit hough 

 usually there is a tendency toward a subopposite arrangement, 

 markedly so in several specimens. Leaflets normally lanceolate, indi- 

 viduals of the same leaf about of a size, usually markedly decurrent, 

 but variable in this respect. The proximal leaflets are always less 

 decurrent than the pair next above, and in some cases even have short 

 petioles. The upper leaflets are remarkably variable, sometimes with 

 an abnormal decurrent wing which joins the inner lamina of the next 

 lower pair of leaflets; at other times the rachis entirely lacks awing. 

 The leaf may be terminated abruptly by a pair of leaflets variously 

 coalesced or the three apical leaflets may be variously united, their 

 lamina may be almost symmetrical or markedly inequilateral, their 

 margins showing a tendency toward undulation, and occasionally a 

 leaflet is divided into a basal and an apical part by a sharp constric- 

 tion on one side near the middle of the blade, ranging in size from 

 the small forms upon which Fontaine founded his species Sapindopsis 

 parvifolia and which are 1.6 cm. long and 0.4 cm. wide to forms 

 which approach Sapindopsis magnifolia in size and are 10 cm. long 

 and 1.5 cm. wide. The average dimensions of a large number of 

 specimens are, however, 6 to 7 cm. long by 1 to 1.3 cm. wide. 



Leaves thick, with smooth surface. Rachis and midrib stout. 

 Venation more prominent than in the other species, but still very 

 faint, with the exception of the secondaries, which while fine are more 

 conspicuous than in the other species. Secondaries forming a wide 

 angle with the midrib, nearly straight for two-thirds of the distance 

 to the margin, where they bend sharply upward and join the secondary 

 next above b}^ a but slightly curved arch. As the secondaries are 

 numerous and almost uniformly spaced the venation has much the 

 appearance of a Eucalyptus, except that the marginal hem is much 

 broader than in that genus. 



This species is exceedingly abundant, at various localities in the 

 Patapsco formation and is by far the most characteristic species of 

 that formation, although it has not been detected at certain other 

 undoubted Patapsco horizons. It is the only species of the genus 

 which has been recorded outside of the Maryland- Virginia area, 

 occurring in the Fuson formation along Oak Creek, Wyoming, where 

 Proc.N.M. v<>1.38— 10 41 



