Endemic

Latin nutans, nodding, drooping, alluding to the drooping, fertile tips of the plant.

Plants medium-sized, terrestrial or epi-phytic. Stems erect or pendulous, unforked to 2-forked, 20-35 cm long, 3-4 em wide at bases, stout and stiff, sterile portions usually gradually transitional to fertile portions. Sterile leaves close, spreading, arranged in 6 rows, not overlapping, flat, linear-lanceolate, 13-20 x 2-3.5 mm, entire, stiff, coriaceous, bases narrowed, tips acute, midribs not prominent, blending more or less gradually into lanceolate fertile leaves. Fertile leaves only slightly different from sterile ones but smaller, 10-20 x 1.5-2.5 mm, sides nearly straight, only slightly wider at bases. Strobili unbranched to 1-branched, 1/3-2/3 stem width.

A very rare federally listed endangered species historically known from the Wahiawa Mountains of Kaua'i and Ko'olau Mountains of O'ahu; currently known from fewer than ten plants, 500-600 m, in the Ko'olau Mountains, O'ahu. This species has sporangium-bearing strobili that are less differentiated than those of Huperzia phyllantha.

The type specimen of Huperzia nutans may actually be an intermediate form between what is now considered typical H. nutans and H. phyllantha. It has a more abrupt transition between larger fertile and smaller sterile leaves than is found on specimens of H. nutans, which have a more gradual transition. See discussion under the hybrid at the end of the treatment of this group and the illustrations of this species.

Huperzia nutans may be distinguished from H. phyllantha by its much wider, unbranched or 1-branched strobili gradually transitional from the sterile stem and by its stiff, pointed sterile leaves arranged in 6 rows.