Fontanum means growing in running waters.
Rhizome: erect, short, scales clathrate, brown, lanceolate, to 4 mm.
Frond: 15 cm high by 5 cm wide, evergreen, monomorphic, blade/stipe ratio: 3:1.
Stipe: blackish at base for 2 cm or less, then green above, brown scales at base, becoming hair-like above, then the rachis almost glabrous, vascular bundles: 2 C-shaped, back to back, uniting to 1 upwards to an X-shape.
Blade: 2-pinnate-pinnatifid, lanceolate, widest above the middle of the blade, light green to gray-green, herbaceous, glabrous.
Pinnae: 10 to 20 pair, alternate, anadromic, basal pinnae more distant; pinnules up to 5 pair at the widest part of the frond, diminishing to 2 at the base; margins coarsely incised; veins free, forking.
Sori: linear, along a vein, indusium: whitish, entire, opening outwards, sporangia: dark brown, covering the segments at maturity.
Habitat: calcareous rocks in relatively dry situations.
Distribution: central Europe, Himalayas.
Hardy to -25░C, USDA Zone 5.
A small, lacy, narrow-bladed, elegant Asplenium with smaller pinnae at the base than the middle.