Lycopodium serratum Thunb. var. subintegrum Hillebr.; Huperzia sulcinervia sensu auct., non (Spring) Trevis. [Huperzia joebeitelii in unpublished checklists]

Endemic

Latin sub, less than, somewhat, + integer, whole, entire; alluding to the partially entire margins of the leaves.

Plants terrestrial. Stems erect, usually forming small clusters, branching near bases, and again 1-3 x distally, 6-25 x 0.7-1.6 cm, annual constrictions usually distinct. Leaves reflexed to spreading near bases, ascending near tips, imbricate, broadly lanceolate, largest leaves stubby, narrowed, and roughly parallel-sided and entire at bases, mostly 3.5-6 x 1.3-2.5 mm, light green to yellow green, adaxial surfaces lustrous as if covered with yellow varnish, margins serrate along distal 2/3, margins clear yellow, tips obtuse to acute, midveins with adaxial ridges and distinct abaxial grooves when dry. Gemmae 3.5-4 x 3-4 mm.

Usually found on wet, exposed banks in wet forests, 1,220-1,525 m, Kaua'i, O'ahu, Moloka 'i, and Maui.

This species in the past has been incorrectly called Huperzia sulcinervia (Spring) Trevis., the holotype of which was found to be a hybrid between H. erubescens and H. serrata by Beitel.

Huperzia subintegra may be recognized by stubby, broadly lanceolate, stiffly ascending, light yellowish green, lustrous leaves with small to medium-sized teeth.