Histropteris. | FILICES. 17 
A small genus of one or two species, widely distributed through the tropics and 
the South Temperate Zone, extending southwards to the Subantarctic islands. It is 
very closely allied to Pteridium, from which it chiefly differs in the venation, and in 
the absence of the inner indusium. 
1. H. ineisa J. Smith Hist. Fil. (1875) 352.—Rhizome long, creeping, 
rather slender, smooth, producing numerous scattered fronds. Stipes 1-3 ft. 
high or more, stout, erect, smooth and glossy, vellow-brown or red-brown 
when mature, often glaucous when young, naked or slightly scabrous at 
the base. Fronds variable in size, 2-4 ft. long, broadly deltoid or ovate- 
deltoid to ovate-lanceolate, membranous when young, firm in age, quite 
smooth and glabrous, glaucous-green, 2-3-pinnate ; rhachis pale chestnut- 
brown, smooth and polished. Primary pinnae large, 6-12 in. long or more, 
ovate-lanceolate, opposite or nearly so, rather distant, sessile, the opposite 
pairs often almost connate at the base, 2-pinnatifid or the uppermost simply 
pinnate. Secondary pinnae lanceolate, deeply pinnatifid, sometimes pinnate 
at the base. Ultimate segments oblong or oblong-deltoid, obtuse, those of 
the barren fronds often sinuate-dentate or lobed. Veins sometimes all free, 
but usually more or less anastomosing near the costa of the pinnules. Sori 
continuous or interrupted, seldom reaching either the base or apex of the 
segment.—Pteris incisa Thunb. Fl. Cap. (1800) 171 ; Hook. Sp. Fil. ii (1858) 
230; Hook. f. Handb. N.Z. Fl. (1864) 364; Hook. and Bak. Syn. Fil. (1873) 
172; Benth. Fl. Austral. vu (1878) 732; Thoms. N.Z. Ferns (1882) 62 ; 
Field N.Z. Ferns (1890) 96, t. 8, f. 4; Cheesem. Man. N.Z. Fl. (1906) 973. 
P. vespertilionis Labill. Pl. Nov. Holl. ii (1806) 96, t. 245; Hook.f. Fl. Antarct. i 
(1844) 110; Fl. Nov. Zel. 11 (1855) 26. P. Brunoniana Endl. Prodr. Insl. 
Norfolk (1833) 12; A. Cunn. Precur. (1836) n. 202; Raoul Choix (1846) 38. 
P. montana Col. in Tasm. Journ. Nat. Scz. ii (1846) 172.  Litobrochia incisa 
and L. vespertilionis Presl Tent. Pterid. (1836) 149. 
NortTH AND SoutH ISLANDS, STEWART ISLAND, CHaTHAM ISLANDS, AUCKLAND AND 
CAMPBELL IsLANDS, ANTIPODES IsLAND: Abundant throughout, often forming thickets 
on the skirts of woods, &c. Sea-level to 3000 ft. 
Universally spread through the tropics and the South Temperate Zone. In New 
Zealand it attains exceptional luxuriance by the margins of hot springs in the Rotorua 
and Taupo districts, in some localities reaching a height of 12 ft. 
29. PTERIDIUM Gled. 
Rhizome stout, creeping, subterranean. Stipites strong, stout, erect 
and rigid, often remote from one another. fronds large, broad, deltoid, 
much divided, 3-4-pinnate. Veins simple or forked, never anastomosing. 
Sori marginal, linear, continuous, placed on a slender receptacle connecting 
the tips of the veins. Indusium double ; the outer one formed of the reflexed 
marein of the frond, membranous, usually villous or ciliated ; the inner 
less evident, arising from the inner side of the receptacle, sometimes obsolete. 
Sporangia stalked, bursting transversely, girt by an incomplete vertical 
ring. ny 
Treated in the sense of the ‘‘ Pflanzenfamilien ’’ and Christensen’s ‘‘ Index Filicum,”’ 
this is a genus composed of a single highly variable and widely spread species; but 
some authors split it into four or five closely related forms. It is mainly distinguished 
from Pieris proper by the distinctly double indusium. 
