Botrychium subbifoliatum Brack.; B. daucifolium sensu E. Bailey, non Wall.; B. tematum (Thunb.) Sw. subsp. australasiaticum Milde f. subbifoliata Milde

Common names: makou

Endemic

Latin sub-, almost, approaching,+ hi-, two, + foliatum, provided with leaves, in refer-ence to the almost two-leaved arrangement of the fertile and sterile branches of the frond.

Plants small to medium-sized. Rhizomes erect to oblique, with a few unbranched to slightly branched dark, fleshy roots. Fronds fleshy, mostly 2 per plant, 1 arising 7.5-12 cm above the base and frequently a second farther above it (see illustration), 15-45 X 16-28 cm. Stipes of sterile portions of fronds 6-25 cm long. Blades 2-to 3-pinnate, deltate; rachises and costae pale green. Pinnae 3-6 pairs, stalked and deltate near base, adnate and lanceolate to oblong distally, dull green, turning yellow when old, tips usually blunt, basiscopic pinnules of basal pinnae larger than acroscopic pinnules. Ultimate segments oblong to oblong-lanceolate, margins irregularly dentate to serrate. Veins forked several times. Sori borne on erect, slender, 2-to 3-pinnate, fertile spikes, 20-35 cm long, mostly longer than sterile blades, originating from common stipes near ground level, small, sessile, in double rows.

Always rare and now probably extinct. Its habitat was probably on wet, mossy forest floors, 600-1,200 m, all major islands.

Although Sceptridium subbifoliatum has not been seen in the wild for almost seventy years, it may have been overlooked because its fronds resemble smaller fronds of other ferns, especially Marattia douglasii.

Sceptridium subbifoliatum belongs to a distinct genus in the family Ophioglossaceae. It has been placed in the genus Botrychium Sw. by some authors and in Botrychium subgenus Sceptridium (Lyon) R. T. Clausen by others. It is probably most closely related to S. daucifolium found from India and Sri Lanka to the Philippines and Fiji.

Sceptridium subbifoliatum is probably extinct but could be recognized by its fleshy, 2-to 3-pinnate fronds with 3-pinnate fertile spikes arising from the lower blade stalks.

References: Brackenridge (1854, 1857).