Synonym: Polypodium kaulfussii C. Presl; P. pseudogrammitis Gaudich.

Common names: kolokolo, mahinalua

Endemic        

Latin tenellus, delicate, in reference to the small, narrow fronds.

Plants small, narrow, linear, epiphytic. Rhizomes long-creeping, thin, less than 1 mm diam., wiry, black, often forming tangled mats. Fronds erect to spreading, 3-20 x 0.1-0.4 cm, arranged in a tangled compact mass. Stipes 2-15 mm long before widening into blade. Blades narrow, long-linear, pale green, thick, chartaceous, glabrous, margins entire, sometimes sinuate. Sori sparse, irregularly scattered, medial but often so large as to protrude beyond blade margins.

Occurring frequently in small to large epiphytic mats in mesic to wet forests, 365-1,675 m, all major islands.

Grammitis tenella may be recognized by its dense mats offronds; very thin, tangled, black rhizomes; and narrow, linear fronds with irregularly scattered sori that are often large and extend beyond the blade margins.