Flora of New Zealand Series

Stegania fluviatilis R. Br. Prodr. 1810, 152.

Lomaria fluviatilis Spreng. Syst. Veg. 4, 1827, 64.

L. rotundifolia Raoul in Ann. Sci. nat. Sér. 3, 2, 1844, 115.

L. rotundifolia Col. in Tasm. J. nat. Sci. 2, 1846, 179.

Rhizome stout, erect, clad in brown subulate-attenuate paleae c. 1 cm. long; stipites numerous, tufted, paleate at base. Stipes 5-20 cm. long, slender to stout, dark brown, procumbent to ascending, ± paleate, bearing up to 50 pairs of pinnae. Sterile lamina 25-40-(75) × 2-4 cm., linear to narrow-linear, spreading, dull green, submembr. Pinnae up to 2 × 1 cm., oblong to obovate-oblong, slightly narrowed to sessile base or very shortly stalked, subopp. to alt., minutely crenulate-dentate to sinuate. Fertile lamina erect, up to 30 cm. long, linear; pinnae ascending to erect, linear-oblong, up to 2 cm. long. Sori covering whole of undersurface, indusium becoming erose.

DIST.: N., S., St., Ch. Lowland to montane forest from lat. 35º southwards, us. by streamsides. Also N.S.W., Victoria, Tasmania.

HYBRIDISM

Forms linking the spp. membranaceum, lanceolatum and norfolkianum occur. There is fairly good evidence that hybridism plays a part in producing the complex. This is true also of B. capense and B. minus. There is slighter evidence that B. banksii and B. durum cross when they meet.

Colenso's L. rotundifolia was described from specimens collected in "Dense humid woods, near Waikare Lake, in decomposed sandstone soil; Dec. 1841." In W are two Colensoan sheets: (a) "L. rotundifolia var. Woods, mountains near Waikare Lake." Two fronds, with portions of stipes bearing paleae up to 1 cm. long. Sterile lamina 63 cm. long, with pinnae oblong, up to 2 × 1 cm., rhachis stout. Fertile lamina 55 cm. long, rhachis stout, with close-set narrow-oblong pinnae up to 15 mm. long: (b) "L. rotundifolia n. sp. W. Colenso: Woods near Poverty Bay; Dec. 1841." A printed label "TYPE" has been attached subsequently. There are four complete plants and two separate sterile laminae. Stipes very slender, up to 5 cm. long, bearing numerous patent slender paleae. Rhachis slender, paleate. Sterile lamina 10-17 cm. long, linear-lanceolate; pinnae rather distant, up to 12 × 5 mm., oblong to ovate-oblong, submembr., coarsely crenate-dentate. Fertile lamina c. 20 cm. long, linear; rhachis slender to rather stout; pinnae oblong, up to 1 cm. long, in distant subopp. pairs. The status of this form deserves further study.

L. fluviatilis var. ramosa Col. in T.N.Z.I. 20, 1888, 225 was based on specimens from "Dry forests near Norsewood, County of Waipawa; 1882-1886: W.C." The sterile laminae are "forked and branched near the top; branches 4-6 inches long, dichotomous at tips, branchlets 1-21/2 inches long, very narrow . . . sometimes . . . corymbose-crested and much dilated." Comparable aberrant forms are found in other spp.