Volume 3 > Part 1 > Year 1979 > Page 81–82 > Hymenophyllaceae > Gonocormus

3. Gonocormus siamensis Tagawa & K.Iwats.wfo-0001226952

Acta Phytotax. Geobot. 22: 99. f. 3. 1967; S.E. Asian Stud. 5: 40. 1967.

Accepted Name : Crepidomanes minutum (Blume) K.Iwats.

Description : Rhizome creeping, about 0.2 mm diam., more or less densely covered with brownish straight hairs about 0.5 mm long. Stipe terete, slender, 1–1.5 cm long, very narrowly winged only on the uppermost part bearing brownish caducous bristles at the very base, rarely proliferous near base. Fronds oblong in outline, usually gradually narrowing towards acuminate or moderately acute apex, the base cuneate to round, bipinnatifid, 1.5–5 cm long, less than 2 cm wide; pinnae to ten pairs, digitately acute at apex, cuneate at base, to 15 mm long, 3 mm wide, upper ones gradually merging into pinnatifid apex of lamina; pinnules simple or lobed into two to five segments the segments acute or nearly so at apex, entire, narrow, 0.1–0.2 mm broad, with 10–15 rows of longer cells. Sori axial, about 12 mm long, 0.5 mm diam., tubular, the mouth subtruncate or hardly dilated, broadly winged on both sides with wings of about 0.2 mm in breadth.

Thailand : PENINSULAR: Nakhon Si Thammarat (Khao Luang – type).

Distribution : Sumatra (Atjeh).

Ecology : On mossy rocks in dense hill evergreen forests at 1,600 m alt.

Notes: Describing this species as new, we misobserved the proliferation of the lower part of the stipes. However, this species is still distinct from Gonocormus prolifer in its much more finely dissected fronds and their deep green colour. In this species the ultimate segments are usually 2–3 mm long, 0.1–0.2 mm broad, but in G. prolifer they are hardly more than 1 mm in length and 0.3–0.5 mm in breadth. Gonocormus siamensis is known only in the type locality and on Gunong Kemiri in North Sumatra, in a rather restricted area there though abundant in individuals. In the living condition, G. siamensis is deep green and the cell-contents are fill the cells. In the other species, on the contrary, plants are yellowish green or pale green in appearance and the cells have large vacuoles.

E-version notes : For more details see Ferns of Thailand, Laos and Cambodia.