Oak Leaf Fern

FAMILY : Polpodiaceae

Characteristic Features :

Habit : Epiphytes or lithophytes

Rhizome : creeping, branched, densely scaly rhizome, 0.5-1.5 m long, 5-10 cm thick. Scales 10-12 x 1-2 mm, dark brown, linear or lanceolate, acuminate, fimbriate subpeltate.

Leaves : Fronds dimorphic; sterile bracket fronds 30-40 x 25-30 cm, simple; stipe 1-3 cm long, thick; lamina elliptic in outline; cordate at base, lobed; lobes 3-6 x 2-3 cm, ovate to ovate-lanceolate, obtuse or rounded; thick coriaceous; costa and primary veins thick, raised above and below; veinlets copiously anastomosing, raised above and below; fertile fronds 60-80 x 40-50 cm, simply pinnate; stipe 12-15 x 0.5-0.8 cm, grooved above, rounded beneath; lamina broadly elliptic in outline; pinnae 20-25 x 3-4 cm, linear or oblong-lanceolate, acuminate, margins usually wavy; costa, costules and veinlets raised above and below, anastomosing. Sori 1-1.5 mm in diameter, dark brown, many on vein endings. Sporangial capsule 312 x 250 µm, subglobose, stalk 500-625 µm long.

Spores : 50 x 37.5 µm, brown, ellipsoid with spinous perine.