DESClilPTION OF THE SPECIES. 103 



ASPIDIUM MACKOCARPUM, Sp. IIOV. 

 Plat.- XVII. I'iK. ii. 



Sterile frond not seen; fertile frond showing only ii skeleton imprint ; 

 prineij)id rachis stout and rigid; plant most probably arborescent ; racliis 

 of the ultimate pinna' stout and rigid ; shape and dimensions of the pin- 

 nules not disclosed ; apparently large, elongate-oblong, attached by the 

 entire base, alternate ; midnerve rather slender, straight ; lateral nerves 

 simple, and bearing at their summits the sori arranged in a I'ow on each 

 side of the midrib. The sori are very large, reniform in shape, and seem 

 to have been situated near the margin of the pinnules. Under a good lens 

 the sj)orangia may be seen arranged often in a band near the margin of 

 the sori. 



Locality: Red clay ball in the banks of Dutch Gap Canal; rare. 



This plant seems to have been a fine large fern. It is seen only as an 

 imprint on the surface of the line clay, giving a skeleton of the more dura- 

 ble parts. The imprints of the sori are very distinct. Tiie sterile form was 

 not seen. This seems to be a species distinct from all described ones. 



Asi'IinUM MICROCARPUM, Sp. UOV. 

 Plate LIX, Figs. S, li> ; Plate LX, Pigs. 6,7. 



Frond tripinnate; Sterile forms have the pinucie of ultimate order 

 short, subopposite, with pinnules towards the base separate and rather 

 remote, slightly decurrent, obtuse, oblong and subopposite, but towards the 

 tips graduating into lobes and teeth which are ovate-obtuse ; leaf-sub- 

 stance thick ; lateral nerves in each pinnule or lobe composed of a mid- 

 nerve, which on each side sends off alternately branches which fork or are 

 simple. Fertile portions of the frond have sometimes sterile and fructified 

 pinnules on the same pinna, but usually the fructified pinnules are on 

 distinct parts of the frond, and then the specimens found show only the 

 skeletons of the sori and nerves, the sori by their arrangement giving the 

 outlines of the pinnules ; sori very minute, visible distinctly only with the 

 help of a strong lens ; rounded in shape, and arranged in a row on each 

 side of the midnerve, placed at the summit of a simple lateral nerva 



