304 THE POTOMAC OE YOUNGER MESOZOIC FLORA. 



whicli run nearly at right angles with the connected nerves, forming an 

 irregular, slender, lax reticulation ; ultimate reticulation not seen ; leaf-sub- 

 stance mostly thin. 



Under the head of CeJastrophyllum I group a number of small leaves, 

 which mostly have the nervation too slender and poorly preserved to enable 

 one to fix the character with any definiteness. The placing of these in a 

 group based on affinities with the Celastrinece is of course, under such cir- 

 cumstances, only provisional. On the whole, the general character of 

 these leaves is nearer to Celastrus than to any other living plant. They 

 form a considerable element in the Potomac flora, although no species fur- 

 nishes, so far as found, any great number of individuals. 



Celastkophyllum arcinerve, sp. nov. 



Plate CXLVI, Fig. 3. 



Shape of leaf not seen, probably oval or elliptical ; midnerve compara- 

 tively strong ; leaf-substance thin ; primary nerves very slender but com- 

 paratively distinct, going off at an acute angle and curving strongly upwards 

 towards the tip of the leaf, running for a long distance parallel to one 

 another, and gradually n earing the margin, bent into a series of bow- 

 shaped arches, which are connected by a regular series of cross-bars or 

 nerves, going off nearly at right angles and forming a series of large pen- 

 tagonal meshes filled by small nearly rectangular meshes ; the ultimate 

 reticulation formed of mainly pentagonal or hexagonal meshes. 



Localit)- : Fredericksburg ; very rare. 



This plant differs in some points of the nervation from the others 

 grouped under the head of CelastrophyJhim, except perhaps C. lafifoliuni, to 

 be described later. It is on the whole considerably like Celastrus irif/ynus, 

 and also resembles C. ruber. 



Celasteophtllum proteoides, sp. nov. 



Plate CXLVI, Fig. 5. 



Leaf small, elongate-elliptical, narrowed gradually to the base into the 

 petiole; leaf-substance thin; no nerves seen; they must be very slender. 

 Locality : Fishing hut above Dutch Gap Canal. 



