Ferns of Thailand, Laos and Cambodia

Family

Psilotaceae

Nomenclature

Psilotum nudum (L.) P.Beauv., Prod. Aethéog.: 112. 1805; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 26. 1976; Tagawa & K.Iwats., Fl. Thailand 3: 5. 1979; Kiew, Fl. Pen. Malaysia, Ser. I, Ferns & Lycoph. 1: 90. 2010. – Lycopodium nudum L., Sp. Pl.: 1100. 1753. – Type: India, LINN No. 1257.1 (lectotype LINN).

Psilotum triquetrum Sw., Syn. Fil.: 117. 1806; Hosseus, Beih. Bot. Centralbl. 28(2): 367. 1911; Bonap., Not. Ptérid. 14: 70. 1923; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 596, f. 64.4 & 64.5. 1951; Larsen, Dansk Bot. Ark. 23: 59. 1963.

Description

Rhizome creeping, dichotomously branching at irregular intervals, 0.5-1.5 mm in diameter, densely beset with brown to dark brown rhizoids. Aerial stems fasciculate, erect, patent, or pendulous, 10–60 cm in height, green, glabrous, dichotomously branching several times in upper portion, grooved, with several distinct ridges 0.5–1.5 mm in diameter. Scaly projections small, to 1 mm long, oval with subulate apex, irregularly and sparsely borne on ridges. Synangia borne adaxially to the projections, glabrous, about 2 mm in diameter, green at first, yellow when mature , with lemon-yellow or paler spores.

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai, Tak; NORTH-EASTERN: Loei, Khon Kaen; SOUTH-WESTERN: Kanchanaburi, Prachuap Khiri Khan; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Chon Buri, Chanthaburi; PENINSULAR: Chumphon, Ranong, Surat Thani, Nakhon Si Thammarat, Phatthalung.

Distribution in Laos

Hua Phan, Khammoune, Xieng Khouang.

Wider Distribution

Tropics and subtropics throughout the world (type from India), north to Jeju Island (South Korea).

Ecology

Usually epiphytic on mossy tree-trunks in dense forest or in light shade at low to medium altitudes.

Proposed IUCN Conservation Assessment

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

Voucher specimens - Thailand

Pooma et al. 6698, Ranong (A, BKF, E); Middleton et al. 5401, Phatthalung, Khao Kram Waterfall (E).

Voucher specimens - Laos

Poilane 1908, Hua PHan, Muong Pun (P); Delacour s.n., Khammouane (P); Poilane 2422, Xieng Kouang (P).

	Ferns of Thailand, Laos and Cambodia
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Psilotum nudum (L.) P.Beauv. Family Psilotaceae Nomenclature Psilotum nudum (L.) P.Beauv., Prod. Aethéog.: 112. 1805; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 26. 1976; Tagawa & K.Iwats., Fl. Thailand 3: 5. 1979; Kiew, Fl. Pen. Malaysia, Ser. I, Ferns & Lycoph. 1: 90. 2010. – Lycopodium nudum L., Sp. Pl.: 1100. 1753. – Type: India, LINN No. 1257.1 (lectotype LINN). Psilotum triquetrum Sw., Syn. Fil.: 117. 1806; Hosseus, Beih. Bot. Centralbl. 28(2): 367. 1911; Bonap., Not. Ptérid. 14: 70. 1923; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 596, f. 64.4 & 64.5. 1951; Larsen, Dansk Bot. Ark. 23: 59. 1963. Description Rhizome creeping, dichotomously branching at irregular intervals, 0.5-1.5 mm in diameter, densely beset with brown to dark brown rhizoids. Aerial stems fasciculate, erect, patent, or pendulous, 10–60 cm in height, green, glabrous, dichotomously branching several times in upper portion, grooved, with several distinct ridges 0.5–1.5 mm in diameter. Scaly projections small, to 1 mm long, oval with subulate apex, irregularly and sparsely borne on ridges. Synangia borne adaxially to the projections, glabrous, about 2 mm in diameter, green at first, yellow when mature , with lemon-yellow or paler spores. Distribution in Thailand NORTHERN: Chiang Mai, Chiang Rai, Tak; NORTH-EASTERN: Loei, Khon Kaen; SOUTH-WESTERN: Kanchanaburi, Prachuap Khiri Khan; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Chon Buri, Chanthaburi; PENINSULAR: Chumphon, Ranong, Surat Thani, Nakhon Si Thammarat, Phatthalung. Distribution in Laos Hua Phan, Khammoune, Xieng Khouang. Wider Distribution Tropics and subtropics throughout the world (type from India), north to Jeju Island (South Korea). Ecology Usually epiphytic on mossy tree-trunks in dense forest or in light shade at low to medium altitudes. Proposed IUCN Conservation Assessment Least Concern (LC). This species is widespread and not under any known threat. Voucher specimens - Thailand Pooma et al. 6698, Ranong (A, BKF, E); Middleton et al. 5401, Phatthalung, Khao Kram Waterfall (E). Voucher specimens - Laos Poilane 1908, Hua PHan, Muong Pun (P); Delacour s.n., Khammouane (P); Poilane 2422, Xieng Kouang (P). Habit Whole plant Young sporangium Mature sporangia
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Psilotum nudum (L.) P.Beauv.