EXPLANATION OF PLATES I. AND II. 411 



rounded into the slightly concave sides, and rounded again 

 towards the point which is deficient. Five principal veins 

 originate from the footstalk, the lower pair, which run 

 near the margin of the lamina, being less conspicuous than 

 the other three. The mid-rib is straight, the vein on each 

 side of it curved in the segment of a circle ; so that were 

 the leaf complete, the three would be found to meet at the 

 point, as in No. 4. Numerous curving and forking branches 

 spring from all. The areolae are of very various sizes, and 

 their surfaces, when viewed with a microscope, are seen to 

 be minutely granular, indicating minute pits in the upper 

 side of the leaf. 



No. 9. 



Impressions of a penniform leaf resembling that of 

 Morus alba in its general outline and the character of its 

 veins, are pretty numerous. Both surfaces seem to have 

 been quite smooth, there being no evidences of the exist- 

 ence of any pubescence. The central nerve or mid-rib, 

 and the primary lateral ones, are very distinctly impressed 

 in the matrix ; and the connecting ones of the second order, 

 which run from one lateral branch to another, are more 

 conspicuous than those of the mulberry. They vary, from 

 being almost straight and parallel to each other, to a 

 greater or less degree of curvature, or even a pointed arch, 

 in the middle of their length, and towards the margin of 

 the leaf are branched and pass gradually into reticulations. 

 The minor veins are much less prominent, and form minute 

 meshes of no uniform shape, but generally oblong, and from 

 four to eight-sided, having a strong resemblance to those of 

 the mulberry. The minute areas are flat and smooth. The 

 lateral veins spring from the mid-rib in pairs, but, except 

 at the base of the lamina/not exactly opposite to each other. 

 From the footstalk two lateral branches spring together 

 with the mid-rib, forming, as in the mulberry, a triple- 

 ribbed leaf; but there is a greater fulness of the lamina 



