Family

Gleicheniaceae

Nomenclature

For the species

Dicranopteris linearis (Burm.f.) Underw., Bull. Torrey Bot. Club 34: 249. 1907; C.Chr., Contr. U.S. Natl. Herb. 26: 330. 1931; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 49. 1939; Holttum, Reinwardtia 4: 275. 1957; Holttum, Fl. Males., Ser. II, Pterid. 1: 33, f. 12, 14f–i & 16. 1959; Holttum, Dansk Bot. Ark. 20: 16. 1961; Holttum, Dansk Bot. Ark 23: 228. 1965; Ching, Fl. Reipubl. Popularis Sin. 2: 118. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 3(3): 73.1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 36. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 55. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 32, 33, 78. 2000; Newman et al., Checkl. Vasc. Pl. Lao PDR: 27. 2007; Leti et al., Fl. Photogr. Cambodge 553. 2013. – Polypodium linearis Burm.f., Fl. Indica: 235, t. 67, f. 2. 1768. – Gleichenia linearis (Burm.f.) C.B.Clarke, Trans. Linn. Soc. London, Bot. 1: 428. 1880; Bedd., Handb. Ferns Brit. India: 4, f. 1. 1883; Christ, Bot. Tidsskr. 24: 111. 1901; C.Chr., Bot. Tidsskr. 32: 349. 1916; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 49. 1939; Holttum, Rev. Fl. Malaya ed. 1, 2: 68, f. 16. 1955 [‘1954’].

Polypodium dichotomum Thunb., Syst. Veg., ed. 14 (J. A. Murray): 938. 1784. – Dicranopteris dichotoma (Thunb.) Bernh., J. Bot. (Schrader) 1801: 38. 1806; Newman et al., Checkl. Vasc. Pl. Lao PDR: 27. 2007.

For Dicranopteris linearis (Burm.f.) Underw. var. tetraphylla (Rosenst.) Nakai

Dicranopteris linearis (Burm.f.) Underw. var. tetraphylla (Rosenst.) Nakai, Bull. Natl. Sci. Mus., Tokyo 29: 67. 1950; Holttum, Fl. Males., Ser. II, Pterid. 1: 36, f. 12b. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 36. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 56. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 79. 2000. – Gleichenia linearis (Burm.f.) C.B.Clarke var. tetraphylla Rosenst., Repert. Spec. Nov. Regni Veg. 13: 213. 1914.

For Dicranopteris linearis (Burm.f.) Underw. var. subpectinata (Christ) Holttum

Dicranopteris linearis (Burm.f.) Underw. var. subpectinata (Christ) Holttum, Reinwardtia 4: 277. 1957; Holttum, Fl. Males., Ser. II, Pterid. 1: 35, f. 12c & 16. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 36. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 56. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 79. 2000. – Gleichenia subpectinata Christ, Bot. Tidsskr. 24: 111. 1901. – Gleichenia linearis (Burm.f.) C.B.Clarke var. subpectinata (Christ) C.Chr., Bot. Tidsskr. 32: 349. 1916. – Gleichenia linearis (Burm.f.) C.B.Clarke var. alternans auct. non Mett.: Holttum, Rev. Fl. Malaya ed. 1, 2: 70, f. 14e. 1955 [‘1954’].

For Dicranopteris linearis (Burm.f.) Underw. var. montana Holttum

Dicranopteris linearis (Burm.f.) Underw. var. montana Holttum, Reinwardtia 4: 276. 1957; Holttum, Fl. Males., Ser. II, Pterid. 1: 36. 1959; Boonkerd & Pollawatn, Pterid. Thailand: 79. 2000.

Description

Terrestrial. Rhizome widely creeping, hairy. Primary rachis-branches usually twice or thrice forked, the two branches at each fork nearly equal; ultimate branches 15–30 cm long, 4–7 cm wide; ultimate segments linear, entire, round at apex, up to 4 mm broad; texture firm, lower surface slightly glaucous, glabrescent, veins more or less prominent on lower surface and hairy .

There are several varieties included in this species . Among them the following are known from Thailand.

Key to the varieties in Thailand

1. Accessory branches not always present at ultimate fork…2
1. Accessory branches always present at ultimate fork…3
2. Branches at each fork of a lateral branch-system approximately equal; lateral branch-systems forked 1–3 times… var. linearis
2. Branches at successive forks alternately unequal; lateral branch-systems on well-grown plants forked at least 3 times… var. subpectinata
3. Ratio of length to width of branches commonly 2:1; costules c. 3 mm apart, segments of lamina 2.5–3 mm wide… var. tetraphylla
3. Ratio of length to width greater; costules more widely separated… var. montana

Distribution in Thailand

Dicranopteris linearis (Burm.f.) Underw. var. linearis

NORTHERN: Chiang Mai, Chiang Rai, Lamphun, Lampang; NORTH-EASTERN: Loei; SOUTH-WESTERN: Prachuap Khiri Khan; SOUTH-EASTERN: Prachinburi, Chanthaburi, Trat; PENINSULAR: Chumphon, Ranong, Surat Thani, Phuket, Nakhon Si Thammarat, Trang, Yala.

Dicranopteris linearis (Burm.f.) Underw. var. tetraphylla (Rosenst.) Nakai

NORTH-EASTERN: Loei.

Dicranopteris linearis (Burm.f.) Underw. var. subpectinata (Christ) Holttum

NORTHERN: Lampang; SOUTH-EASTERN: Trat; PENINSULAR: Trang.

Dicranopteris linearis (Burm.f.) Underw. var. montana Holttum

NORTHERN: Chiang Rai.

Distribution in Laos

Khammouane, Luang Phrabang, Xieng Khouang.

Distribution in Cambodia

Kampot, Koh Kong, Siem Reap.

Wider Distribution

Dicranopteris linearis (Burm.f.) Underw. var. linearis

Tropical and subtropical regions in the Old World, north to Central Japan.

Dicranopteris linearis (Burm.f.) Underw. var. tetraphylla (Rosenst.) Nakai

South China (Guangdong, Hainan), Indochina and Sumatra.

Dicranopteris linearis (Burm.f.) Underw. var. subpectinata (Christ) Holttum

Peninsular Malaysia, Borneo, Sumatra, and their neighbouring islands.

Dicranopteris linearis (Burm.f.) Underw. var. montana Holttum

Sri Lanka, S India, Sikkim, W Malesia, Moluccas.

Ecology

Dicranopteris linearis (Burm.f.) Underw. var. linearis

In clearings usually at edge of forest in open or half-shaded places at low to medium altitudes.

Dicranopteris linearis (Burm.f.) Underw. var. tetraphylla (Rosenst.) Nakai

Reported from rather dry clearing at edge of forest by the river at 1100–1200 m alt.

Dicranopteris linearis (Burm.f.) Underw. var. subpectinata (Christ) Holttum

On rather dry slopes in open areas at edge of forest at low altitudes.

Dicranopteris linearis (Burm.f.) Underw. var. montana Holttum

Edge of forest and in clearings at medium to high altitudes.

Proposed IUCN Conservation Assessment

All varieties found in Thailand are Least Concern (LC).  All are common and widespread.

Notes

We have not attempted to distinguish the varieties in Thailand.

Voucher specimens - Cambodia

Long et al. CL518, Koh Kong (P); Viboth R4-5, Koh Kong, Thma Baing (P); Long et al. CL254, Siem Reap (P).