Common names: 'ekaha, 'ekaha kuahiwi ("moun-tain 'ekaha"), 'iikaha, 'ekahakaha (a juvenile form of 'ekaha) (P. & E.), bird's-nest fern

Indigenous

Latin nidus, nest, alluding to the nestlike appearance of the fern.

Plants large, epiphytic or terrestrial. Rhizomes thick, short, erect. Fronds simple, sessile, radiating in a shuttlecock fashion, broadly lanceolate, 50-100(-200) x 8-20 cm, entire, leathery; midrib wide, dark, flat-tened on upper surface, mostly thick and round beneath, sometimes triangular or trapezoidal. Veins free, unforked or 1-forked, anastomosing at margin to form a continuous marginal commissural vein. Sori on almost every vein in the distal 1/2-2/3 of frond, linear, to 9+ cm long, extending from near midrib to 1/2-2/3 distance to margin. Indusia extending length of sori, narrow. 

Relatively common epiphyte, often in tree crotches or at bases of large branches, occasionally terrestrial, 40-610 m, all major islands. Also native to Polynesia, tropical Asia, and tropical Australia east to Mauritius and Madagascar.

In mesic to dry forests in the southern Ko'olau Mountains of O'ahu and on Maui, A. nidus is frequently found with clusters of Haplopteris zosterifolia hanging from its rhizome. From a distance the Haplopteris fronds appear to be aerial roots. This association is found in very young plants, and it is not clear whether H. zosterifolia is epiphytic on A. nidus or the reverse. There may be a mutual advantage.

The abaxial midrib of most Hawaiian collections of A. nidus is round, but others occasionally have either trapezoidal or sharply keeled midribs, suggesting that there may be more than one species in Hawai 'i. This taxon needs careful study to establish the identity of plants found in Hawai 'i.

The dark midribs of the fronds were woven into lau hala mats by the Hawaiians to provide a color contrast. 'Ekaha was also used to cover the residual stump after a tree had been felled for canoe making.

The radiating, simple-bladed fronds of Asplenium nidus suggest a large bird's nest. The sori are longer than those of any other Hawaiian Asplenium species.