L. Lesquereux on the Coal Formations of North America. 209 
ropteris. It has a tripinnately divided frond, with open, flexu- 
ous, ovate-lanceolate primary pinne and linear secondary pinne. 
he pinnules, united together up to the third of their length, 
More obtuse and as the upper pinne are decurrent on the rachis, 
aa. to the mainstem. The medial nerve 
Tableau des Genres age 24, : Q 
long, pinnatifid, with grncuien attached to the rachis by their 
Whole base, generally united together at the base, oblong, obtuse, 
oy peaite or perpendicular, simple, once, twice, rarely thrice, 
€ 
The modificati f Brongniart’s definition concerns only the 
characters Salitie: tices the ens of the pinnules: oblong, entire, 
“les that 
Guta Sternb., whose leaflets are sometimes sharply serrate. As 
will be seen be ae 
“ntire, and thus the serrature of part of the leaflets may be con- 
as abno: ; sy 
Prof. Repaguart 43 his Zableau des Genres has farther — 
ded the genus Pecopieris into three subgenera, according to the 
"éction and the number of the divisions of the veins. As these 
“baracters are not always permanent in the same species, these 
A% Jour. Scr.—szconn Senres, Vor. XXXII, No. 98—Mancw, 1862. 
27 
