ASPLENIACEAE

SPLEENWORT FAMILY

Alan R. Smith and Thomas Lemieux

Rhizome-scale cells with adjacent walls dark brown to blackish, external clear
Leaf: petiole in transverse section with 1 X-shaped or 2 back-to-back C-shaped vascular strands; segment veins generally free
Sporangia in linear to oblong sori along veins; indusia linear, opening away from veins; stalk cells in 1 row; spores elliptic, winged
Genera in family: ± 10 genera (limits disputed), 650 species (most in Asplenium): worldwide, especially tropical.

ASPLENIUM

SPLEENWORT

Plants in soil or on rocks; rhizome generally short-creeping to erect
Leaves often tufted, generally glabrous; 1° axis often ± winged; blade simple or 1–many-pinnate, rarely forked; 1° leaflets often asymmetric, upward side more developed
Sporangia in linear sori; indusia persistent, covering sori when young, later reflexed
Etymology: (Greek: spleen)

Native

A. septentrionale (L.) Hoffm.

NORTHERN SPLEENWORT

Leaves simple or 1–2-forked, many, densely clustered, 5–15 cm; petiole 2.5–12 cm, ± 0.5 mm wide, unwinged, red-brown at base, greenish above, dull; blade generally 1–2 mm wide, narrowly linear, sometimes with small, ± linear, generally sterile teeth near or at tip
Sporangia: sori 5–15 mm, generally 1 per segment but sometimes appearing to have as many as 4, corresponding to generally the same number of teeth per segment
Chromosomes: 2n=144
Ecology: Crevices of granite rocks
Elevation: 2500–3350 m.
Bioregional distribution: High Cascade Range, s High Sierra Nevada
Distribution outside California: to Oregon, South Dakota (also WV), Texas, n Baja California, Europe, Asia