DESCEIPTION OF SPECIES— FILICBS. 61 



LYGODIUM, Sw. 



liyg:o dill III ne 11 roptcroidcs, Lesqz. 



Plate V, Figs. 4-7 ; Plate VI, Fig. 1. 



Lygodhmi nmropteroides, Lesqx., Annual Report, 1870, p. 384; 1871, p. 284. 



Pinnules cordate, two to five palmately lobed, divisions oblong or obovate, lanceol.ite, obtuse; 

 middle nerve thin ; lateral veins close, numerous, dichotomous. 



This fine species covers by its remains, mostly leaflets, with rhizomas 

 and their divisions, large and numerous specimens of soft-grained yellow clay. 

 Fragments of stems or rachis are rare, even, indeed, it is uncertain if the 

 thinly striated, flat fragments of woody tissue, varying from two to twelve 

 millimeters in width, represent stems or rachis, for they may be merely half- 

 decomposed branches of the rhizomas. The leaflets, narrowed downward to a 

 cordate base, are two to four palmately parted to the middle more generally, 

 sometimes lower ; the divisions, oblong, enlarged upward, and very obtuse or 

 linear-lanceolate and obtusely pointed, are four to eight ceiitimeters long, even 

 more, from the base of the leaflets ; the lateral ones generally shorter, all 

 obliquely diverging, with more or less obtuse sinuses, are entire or slightly 

 wavy on tlie borders. The nervation is simple for each division of the 

 leaflets, the middle nerve of each remaining distinct to tlie base, where it is 

 generally separated from the others by secondary flabellate veins; lateral 

 veins emerging in a very acute angle of divergence, dichotomous, curving in 

 passing to the borders. The lowest veins are forked three to four times, the 

 upper ones only twice, all very close, especially along the borders, where 

 thirty to thirty-three veinlets are marked in one centimeter. The division of 

 the lateral veins is marked in fig. 5 a, enlarged; fig. 5 shows the longest of the 

 divisions of a leaflet, which appears only twice lobed. The rhizomas, two 

 and a half centimeters broad, the largest seen, are pinnately divided in 

 numerous alternate branches, six to eight millimeters broad, narrowly striate, 

 subdivided in branchlets about one millimeter wide, covered with very 

 numerous, close radicles, mostly in right angle, of various length, and of the 

 same thickness in their whole length. Whole large slabs are covered with 

 fragments of these rhizomas and of their branches, one of which is represented 

 in pi. vi, fig. 1. Though the connection to the leaflets is not seen anywhere, 

 they evidently belong to the same species, as no remains of any other kind 

 are preserved upon the same specimens 



By the division and the form of the pinnules, this species is related to 

 Lygodium Gaudini, Heer (Flor. Tert. Helv., i, p. 41, plate xiii, figs. 5-15), 



