Thelypteris wailele Flynn; Cyclosorus wailele (Flynn) W. H. Wagner

Endemic

Hawaiian wailele, waterfall, in reference to its habitat in the spray zone on sheer rock faces at the margins of waterfalls.

Plants small, epipetric, near waterfalls. Rhi· zomes slender, long-creeping, 2.5-4 mm diam. Fronds pendent, 7.5-35 x 3.8-12 cm. Stipes dark brown at base, pale green above. Blades narrow, linear-oblanceo1ate, narrowed at base with 1-4 pairs of smaller pinnae. Pinnae 15-20 pairs, margins slightly lobed to shallowly crenate, tips acuminate, both sides glandular. Veins 1-3 pairs per segment, usually 2 anastomosing to form excurrent veins to shallow sinuses. Sori pericostal to medial. Indusia small, round to reniform.

Restricted to sheer, dripping, wet walls in the spray zones of waterfalls at the backs of valleys, 450-950 m, in the Hanalei and Wai-mea Districts on Kaua 'i.

Christella wailele may be distinguished from C. cyatheoides by its narrow, pendent fronds and slender, creeping rhizomes. It grows only in or near waterfalls on Kaua'i.