Endemic

Latin montanus, pertaining to mountains, in reference to its habitat in mountainous areas.

Fronds stiffly erect, to 23 em long. Stipes 0.7-1 mm diam., narrowly winged bilaterally. Blades linear to sublinear, often with a three-dimensional quality caused by pinnae and pinnules radiating away from plane of blade (fronds resembling bottle-brushes). Ultimate segments linear, tips forming a nest for sori. Sori extending beyond tips of ultimate segments, extending from tips of segments equally from upper and lower surfaces.

Found in or near bogs as a low epiphyte or near the ground in moss mats, 900-1,935 m, on Moloka 'i, Maui, and the Kohala Mountains of Hawai 'i.

Adenophorus tamariscinus var. montanus is a plant of mid-to high-elevation bogs. In lower elevation rain forests it intergrades with A. tamariscinus var. tamariscinus, form-ing a continuum of intermediate forms. Transitional forms are common, some with sori extending beyond ultimate segment tips and flattened fronds, some with subterminal sori and three-dimensional fronds. The extreme form is not the most common.

Adenophorus tamariscinus var. montanus may be recognized by its long, linear fronds with often twisted pinnae that radiate from the plane of the fronds, and pinnules that radiate in the same manner from the pinnae, giving each frond the ap-pearance of a long, narrow bottlebrush. Its sori protrude from the tips of the pinnules, a feature unique in the genus.