Lygodium heterodoxum Kunze

Lygodium heterodoxum Kunze, Farrnkr. 2 : 32. 1849
Hydroglossum spectahile Iviebm. Vidensk. Selsk. Skr. V. 1 : 299. 1849. Hydroglossum heterodoxum. Moore, Index Fil. cxiv1857. Lygodictyon heterodoxum, J. Smith, Ferns Brit. & For. 259. 1866. Fronds several meters long ; rhizome short-creeping, thickly clothed with short blackish few-celled flaccid hairs ; stipe and rachis stramineous throughout, subterete, stoutish, up to 3 mm. in diameter; primary branches evident as mere protuberances upon the rachis or up to 5 mm. long, the terminal bud not invariably abortive ; secondary (geminate) pinnae up to 50 cm. long, petiolate (3-6.5 cm.), rotund-ovate to pentagonal in outline, pinnate or at the base bipinnate, the rachis strongly flexuous, stramineous, narrowly marginate above ; tertiary segments 2-4 pairs, nearly equal in length, the lowermost petiolate (1-4 cm.), cordate at the base, sometimes triangular and pinnate, bearing a pair of shorter alternate quaternary segments at the base, or subpalmately cleft into 3 or 4 elongate quaternary segments similar to the middle tertiary segments, these simple or dichotomously cleft, the divisions equal or unequal ; upper tertiary segments mostly simple, falcate, the uppermost often joined to the terminal segment, this sometimes greatly elongate (up to 30 cm. ) and either single or binate ; middle tertiary segments (or their main divisions ) in general linearoblong, 10-20 cm. long, 1.5-3 cm. broad, or the fertile ones linear-lanceolate and narrower; costae stout, not nodose-articulate at the base, subflexuous, elevated ; veins alternate, oblique, elevated, anastomosing, forming 4 or 5 ranks of areoles upon each side of the costa, the costal row unequally obdeltoid, the outer ones irregularly hexagonal, directed toward the margin ; leaf-tissue rigidly herbaceous, lustrous upon both surfaces, slightly paler below, the veins and costae nearly glabrous, the margins obscurely crenulate-repand ; sporang^ophores up to 6 mm. long, close, sessile, serrate; spores verrucose.
Type locality : Oaxaca, Mexico.
Distribution: Southern Mexico to Costa Rica; also in Venezuela.