298 THE POTOMAC OR YOUNGEE MESOZOIC FLORA. 



an angle of 45°, arch at first slightly forwards, and then bend strongly for- 

 wards to form arching nerves, which run for some distance approximately 

 parallel to the margin, gradually approaching it; these communicate with 

 one another by one strong nei've each to form large spaces approximately 

 pentagonal in form, and by a series of minor nerves, which meet at a large 

 angle, connect witli tlie midrib and primary nerves to form quadrangular or 

 subrliombic primary meshes; the ultimate meshes quadrangular or sub- 

 rhombic and comparatively distinct. 



Localities: 72d mile-post ; bank near Brooke ; White House Bluff. 



Tliis plant is very common at all these localities. It, with *S'. variahUis, 

 makes up the greater part of the fossils at these places. The plant is nuich 

 like S. variabilis, and may j^ossibly be a large variety of it. The leaves, 

 however, are unifonnly thicker in substance than those of that species. 

 They show a greater tendency to short, broad forms, and the midnerve con- 

 tinues remarkably strong to tlie tips of the leaves. The chief cause of sep- 

 aration is tlie nervation, which is quite different from that of S. variabilis, 

 lacking tlie distinct connecting marginal and arching nerve seen in that 

 species. Fragments found indicate leaflets larger than any of those figured. 

 Plate CLIV, Fig. 5, shows an abnormally short thick leaf It may pos- 

 sibly be the terminal one, for this is sometimes different from those lower 

 down. Plate CLII, Fig. 3, gives a pair of large leaves whicli remind one of 

 Hi/mencea, but they are the terminal leaflet of the compound leaf, and one 

 (the right-hand) lateral leaflet ; the other lateral leaflet on the left-hand 

 side has been accidentally torn away. 



Sapindopsis variabilis, sp. nov. 



Plate CLI, Fig. 1; Plate CLII, Figs. 1, 4 ; Plate CLIII, Fig. 3; Plate CLIV, Figs. 2-4; Plate CLV, 



Figs. 2-5. 



Leaves and leaflets small ; leaflets, especially the upper ones, varying 

 much in size, shape, and mode of arrangement; leaves odd or abruptly 

 pinnate ; leaflets narrowly elliptical to lancet-shaped ; leaf-substance leatli- 

 eiy and thick, epidermis dense and glossy ; leaflets normally opposite or 

 subopposite, upper leaflets decurrent normally by a narrow wing, but often 

 losing these features ; the wing diminishes in width on the pairs descending, 



