Family

Dipteridaceae

Nomenclature

Dipteris conjugata Reinw., Syll, Pl. Nov. 2: 3. 1824; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 442. 1941; Holttum, Rev. Fl. Malaya ed. 1, 2: 135, f. 55. 1955 [‘1954’]; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 46. 1967; Acta Phytbtax. Geobot. 23: 52. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 481, f. 49.1 & 49.2. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 32, 78. 2000.

Polypodium horsfieldii R.Br. in Benn., Pl. Jav. Rar. t.1. 1838. – Dipteris horsfieldii (R.Br.) Bedd., Ferns Brit. India: t. 321. 1869; Bedd., Handb. Ferns Brit. India: 336, f. 185. 1883.

Description

Rhizome long creeping on clayey ground, about 1 cm or more diam., bearing fronds remotely, densely covered with hairs; hairs 4 to 5 mm long, 0.2 mm diam., sometimes the basal portion consisting of a few rows of cells, stiff, dark brown, shining. Stipes up to 2 m long, densely hairy at base, glabrous above, stramineous to brown. Laminae up to 50 cm or more long, 70 cm wide, bilobed almost to the base, the lobes spreading fan-shaped, divided more than halfway to the base into four unequal segments which are again lobed once or more times less deeply and unequally; ultimate segments narrowly subtriangular, gradually narrowing towards caudately acuminate apex, irregularly waved at margin; main veins dichotomously branched several times, 2–4 main veins entering into ultimate segments; venation copiously anastomosing with included veinlets; coriaceous, green on upper surface, paler or glaucous beneath. Sori small, numerous, irregularly scattered all over the lower surface of fronds, without indusia, mixed with club-shaped paraphyses .

Distribution in Thailand

PENINSULAR: Surat Thani, Phangnga, Nakhon Si Thammarat, Trang, Yala.

Distribution in Cambodia

Kampot

Wider Distribution

Vietnam and Cambodia, throughout Malesia to Polynesia and Australia, northwards to Taiwan and S Ryukyus (Iriomote).

Ecology

Usually on clayey slopes in or at edge of evergreen forests and in the places with sufficient light at high altitudes higher than 1000 m in Peninsular, rather common and abundant.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is widespread and not under any known threat.

Voucher specimens - Thailand

Middleton et al. 5505, Nakhon Si Thammarat, Khao Ram Rom (E).