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. vespertinum Maxon

Leaves 1-pinnate, many, clustered, 8–30 cm; petiole 1–5(8) cm, generally 0.5–1 mm wide, unwinged, dark red- to purple-brown, shiny; blade generally 1–2.5 cm wide, linear; 1° leaflets 20–30 pairs, generally 5–12 mm, 5 mm wide, oblong, margin shallowly lobed ± throughout
Sporangia: sori generally 0.5–1.5 mm, generally 2–6 pairs per 1° leaflet
Ecology: Base of overhanging boulders
Elevation: 500–1000 m.
Bioregional distribution: South Coast, San Gabriel Mountains, Peninsular Ranges
Distribution outside California: n Baja California
Horticultural information: DRN, SHD: 2, 3; DFCLT.