Rhizome erect to short-creeping; plant usually solitary, fronds erect; paleae light brown, lanceolate to narrowly lanceolate, acute to broadly acute, 1.2-3.7 × 0.25-0.75 mm. Stipe ± indistinct, winged to base; stipe hairs absent or very rare, whitish, to 1.0 mm long. Lamina linear-oblanceolate, acute to broadly acute, (1.6-) 3.3-8.1 (-13.6) × (0.2-) 0.24-0.42(-0.5) cm; lamina hairs absent or very rare, similar to those of stipe; texture thinly coriaceous to coriaceous; veins visible to invisible, endings not darkened; midrib slightly raised below, darker than lamina. Sori subglobose to oblong, oblique or nearly parallel to midrib, in upper ½ to 2/3 of frond but not usually in apex, 2-19 pairs, 1.5-4.0 × 1.0-2.0 mm, sometimes ± confluent and covering most of frond undersurface when mature; soral vein prolonged or not beyond sorus but not as long as basiscopic vein, neither reaching the margin. Sporangia (200-)226.4- 299.0(-370) mcm long; indurated cells of annulus (10-)10.4-12.4(-15). Spores (25-) 34.3-47.5(-58) mcm diam.

Differt a G. magellanica subsp. magellanica in plerumque habitu solitario, aliquantum frondibus parvioribus, extremis venarum non fuscatis, et aliquantum maioribus sporangiis et sporiis. Rhizoma erectum vel breviter repens; planta plerumque solitaria, frondes erectae; paleae pallide brunneae, lanceolatae vel anguste lanceolatae, acutae yel late acutae, 1.2-3.7 × 0.25-0.75 mm. Stipes ± indistinctus, ad basim alatus; pili absentes vel rarissimi, albidi, ad 1.0 mm longi. Lamina linearo-oblanceolata, acuta vel late acuta, (1.6)-3.3-8.1(-13.6) × (0.2-) 0.24—0.42(-0.5) cm; pili absentes yel rarissimi, eidem pili stipitis; textura tenuiter coriacea vel coriacea; venae manifestae vel non, extremae venarum non fuscatae; costa parum sub lamina prominens, atrior quam lamina. Sori subglobosi vel oblongi, obliqui vel fere ad costam paralleli, in superiore ½-2/3 parte frondis, plerumque non in apice, 2-19 pares, 1-5-4.0 × 1.0-2.0 mm, interdum ± confiuentes et pagina inferiore tengentes ubi maturi; vena sori ultra sorum procurrens vel non, sed non in longitudine venam basalem aequans, non ad marginem accedens. Sporangia (200-)226.4-299.0(-370) mcm longa; cellulae induratae annuli (10-) 10.4-12.4(-15). Sporae (25-) 34.3-47.5(-58) mcm diameter.