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BLECHNACEAE

Mostly terrestrial ferns, sometimes climbers starting from the ground, rhizome mostly erect, sometimes rampant, dictyostelic, bearing dark, basally attached scales. Fronds mostly long stipitate, the stipe with 2 to several bundles in a ring, or many bundles in a more complex arrangement, lamina pinnatifid or pinnate, cometimes simple, lobed, or bipinnatifid, uniform or with strongly contracted fertile pinnae or lobes, glabrous, hairy and/or scaly, veins free to the margin, or anastomosing in a single (rarely more) series of costal areoles. Sori elongate and continuous along a vascular network either side of the midrib, protected by an indusium opening inwards, less often exindusiate, sometimes sori short, occasionally confluent, in 1 - 2 rows; annulus longitudinal, interrupted; spores monolete.

A family of 11 genera world-wide, with c. 240 species. In Papuasia there are 4 genera with c. 33 species. Stenochlaena is the only genus that could be considered aquatic.

Stenochlaena J. Sm.

Moderate to large, high-climbing ferns with scandent rhizomes, often in swamps or beside rivers. Rhizome naked, green, apically bearing many rotund or elongate, peltate scales, radially symmetric, vascular system a complex dictyostele of several large central bundles surrounded by 2 irregular rings of many smaller bundles. Fronds widely spaced, stipes glabrous, +/- decurrent with the rhizome, with corresponding vasculature, the lamina pinnate with alternate pinnae and a terminal pinna similar to the lateral pinnae, dimorphic, the fertile lamina much contracted (in one species bipinnate); the sterile lateral pinnae usually articulate, with a basal acroscopic gland, costate with fine, close, free veins arising from a series of narrow, elongate, costal areoles, coriaceous, glabrous, margin cartilaginous and sharply toothed; fertile pinnae narrow, linear, entire. Sporangia borne in an elogate coena\osorus occupying the area from the costal areoles almost to the margin of the fertile pinnae, supplied by a secondary vascular system, exindusiate, paraphyses lacking, annulus longitudinal, interrupted, of 12 - 20 thickened cells. Spores monolete, translucent, tuberculate or with continuous or broken ribs.

Distribution: A genus of 6 species from Africa, Asia, the Philippines and Indonesia eastwards into the Pacific as far as Tonga and Samoa. There are three species in Papuasia, of which Stenochlaena areolaris is restricted to the crowns of some species of Pandanus (Pandanaceae).

References

Croft, J.R. 1985. Ferns and Fern Allies, in Leach, G.J. & Osborne, P.L. 1985. Freshwater Plants of Papua New Guinea. 33 - 74, f. 6 - 13, pl. 5 - 7.

Holttum, R.E. 1927. Notes on Malayan Ferns. Gard. Bull. Str. Set. 4: 57 - 69, pl. ( 2. On the production of fertile fronds by Stenochlaena palustris, pp. 59 - 61)

Holttum, R.E. 1932. On Stenochlaena, Lomariopsis and Teratophyllum on the Malayan region. Gard. Bull Str. Set. 5: 245 - 313, f. 1 - 39, pl. 1 - 12.

Holttum, R.E. 1937. Further notes on Stenochlaena, Lomariopsis and Teratophyllum. Gard. Bull. Str. Set. 9: 139 - 144.

Holttum, R.E. 1971. The genus Stenochlaena J. smith with description of a new species. Amer. Fern J. 61: 119 - 123.

1 Lower pinnae at least appearing fully articulate when dry, bases of sterile pinnae cuneate; fertile pinnae 2 - 3 mm wide; spores evenly tuberculate throughout… S. palustris
Pinnae not distinctly articulate, bases or sterile pinnae broadly rounded; fertile pinnae c. 5 mm wide; spores with irregularly broken ridges… S. milnei

Stenochlaena milnei Underw.

Synonym: Stenochlaena juglandifolia sensu Holttum non Presl

Scrambling, long creeping fern, or high climbing epiphyte with base rooted to the ground, fronds widely spaced, horizontal to pendulous with drooping pinnae, the rhizome 10 - 15 mm diameter, pale green, sometimes slightly glaucous, smooth, with scattered, dark, small, orbicular scales, especially towards the apex, the growing tip completely covered; fronds 100 - 150 cm long, including stipe 20 - 50 cm long, sterile pinnae for the most part not articulate to the rachis, lanceolate to oblong-lanceolate or oblong, 3 - 5 x 15 - 3- cm, tip acute, slightly attenuate, base often asymmetric, mostly rounded, with a small dark gland on the apical side, margin almost entire to serrulate, especially at the apex; fertile pinnae linear, 4 - 7 x 15 - 30 cm; spores with irregular broken ridges.

Habitat: Most collections indicated well-drained lowland rainforests, but some are from fresh water swamp forests, sago (Metroxylon) swamps, behind mangroves or strand vegetation, along rivers, etc., sometimes in full sun but prefers a partial shade, sometimes with Stenochlawna palustris. Most commonly a scrambling, high-climbing epiphyte; from sea level to 300 m altitude.

Distribution: The Philippines and New Guinea and the Bismarck Archipelago to the Solomon Islands. In New Guinea apparently restricted to along the north coast.

Notes: This species is closely related to Stenochlaena palustris and has often been misidentified in the past. S. milnei is a much more robust plant generally occuring in less swampy conditions than S. palustris. There are very few specimens that are not assignable to either or these species. The young leaves of this species do not appear to be eaten like Stenochlaena palustris, but this may be a reflection of the relative abundance of the two species.

Specimens examined:

West Sepik: Vanimo, Croft 1694; Bewani Ranges, Croft 1703-b
East Sepik: Leitre Village, Sayers in NGF 19578; Maprik, Apangai, Wiakabu in LAE 73564
Morobe: Lae, Argent & Waraka in NGBF 1036, Millar & Holttum in NGF 15794, Verdcourt et al. 4946B; Lake Wanum, Frodin & Naoni in UPNG 7010; Natter Bay, Croft 404
Milne Bay: Cape Vogel, Menapi, Brass 22077; Woodlark Island, Lulumadau, Brass 28807; Fergusson Island, Salamo, Streimann & Lelean in NGF 52572
New Britain: Kervat, Floyd in NGF 7003; Cape Hoskins, Coode & Lake in NGF 32615
New Ireland: Taron, Croft in LAE 68280; Schleinitz Range, Croft & Lelean in LAE 65671
Bougainville: Buin, Craven & Schodde 102; Lolaho, Millar & Vandenberg in NGF 48516
Solomon Islands: Guadalcanal, Honiara, McKee 1643; N Guadalcanal, Nakisi & Babala in BSIP 8224; Santa Ysabel, Maringe Lagoon, Whitmore in BSIP 2253; New Georgia, Roviana Lagoon, Whitmore & Grubb in BSIP 2035

Stenochlaena palustris (Burm.f.) Bedd.

Synonyms: Lomaria juglandifolia Presl; Stenochlaena fraxinifolia Presl; Stenochlaena laurifolia Presl

Scrambling, long creeping fern, or high climbing epiphyte with base rooted to the ground, fronds widely spaced, horizontal to pendulous with drooping pinnae, the rhizome 5 - 7 mm diameter, pale green, sometimes slightly glaucous, smooth, with scattered, dark, small, orbicular scales, especially towards the apex, the growing tip completely covered; fronds 30 - 80 cm long, including stipe 5 - 20 cm long, sterile pinnae for the most part articulate to the rachis, lanceolate to oblong-lanceolate, 1.5 - 3 x 8 - 15cm, tip acute, slightly attenuate, base often asymmetric, mostly cuneate, with a small dark gland on the apical side, argin almost entire to serrulate, especially at the apex; fertile pinnae linear, 2 - 3 x 15 - 25 cm; spores evenly tuberculate.

Habitat: Fresh water swamp forests, sago (Metroxylon) swamps, behind mangroves or strand vegetation, along rivers, marshes and on floating vegetation, sometimes in full sun but prefers partial shade. Most commonly a scrambling, high-climbing ehiphyte in areas subject to periodic inundation, where the base of the rhizome and lower fronds are frequently wet, but also occurs in lowland rainforest in areas free from flooding; from sea level to 300 m altitude.

Distribution: India, throughout southeast Asia, Indonesia and New Guinea from nearly all lowland regions, and northeast Australia, and eastwards to Tonga and Samoa.

Notes: The juvenile leaves of this species are deep reddish. In some areas (Manus, Sepik, Upper Fly, Milne Bay etc.) these young fronds are harvested and cooked as a vegetable. (See also note under Stenochlaena milnei).

Holttum (1927) notes that the production of fertile fronds may be stimulated by a period of dry weather.

Specimens examined

West Sepik: Vanimo, Croft 1694; Bewani Ranges, Croft 1703-b
East Sepik: Leitre Village, Sayers in NGF 19578; Maprik, Apangai, Wiakabu in LAE 73564
Morobe: Lae, Argent & Waraka in NGBF 1036, Millar & Holttum in NGF 15794, Verdcourt et al. 4946B; Lake Wanum, Frodin & Naoni in UPNG 7010; Natter Bay, Croft 404
Milne Bay: Cape Vogel, Menapi, Brass 22077; Woodlark Island, Kulumadau, Brass 28807; Fergusson Island, Salamo, Streimann & Lelean in NGF 52572
New Britain: Kerevat, Floyd in NGF 7003; Cape Hoskins, Coode & Lake in NGF 32615
New Ireland: Taron, Croft in LAE 68280; Schleinitz Range, Croft & Lelean in LAE 65671
Bougainville: Buin, Craven & Schodde 102; Loloho, Millar & Vandenberg in NGF 48516
Solomon Islands: Guadalcanal, Honiara, McKee 1643; N Guadalcanal, Nakisi & Babala in BSIP 8224; Santa Ysabel, Maringe Lagood, Whitmore in BSIP 2253; New Georgia, Roviana Lagoon, Whitmore & Grubb in BSIP 2035

Stenochlaena palustris (Burm.f.) Bedd.

Synonyms: Lomaria juglandifolia Presl; Stenochlaena fraxinifolia Presl; Stenochlaena laurifolia Presl

Scrambling, long creeping fern, or high climbing epiphyte with base rooted to the ground, fronds widely spaced, horizontal to pendulous with drooping pinnae, the rhizome 5 - 7 mm diameter, pale green, sometimes slightly glaucous, smooth, with scattered, dark, small, orbicular scales, especially towards the apex, the growing tip completely covered; fronds 30 - 80 cm long, including stipe 5 - 20 cm long, sterile pinnae for the most part articulate to the rachis, lanceolate to oblong-lanceolate, 1.5 - 3 x 8 - 15 cm, tip acute, slightly attenuate, base often asymmetric, mostly cuneate, with a small dark gland on the apical side, margin almost entire to serrulate, especially at the apex; fertile pinnae linear, 2 - 3 x 15 - 25 cm; spores evenly tuberculate.

Habitat: Fresh water swamp forests, sago (Metroxylon) swamps, behind mangroves or strand vegetation, along rivers, marshes and on floating vegetation , sometimes in full sund but prefers partial shade. Most commonly a scrambling, high-climbing epiphyte in areas subject to periodic inundation, where the base of the rhizome and lower frond s are frequently wet, but also occurs in lowland rainforest in areas free from flooding; from sea level to 300 m altitude.

Distribution: India, throughout southeast Asia, Indonesia and New Guinea from nearly all the lowland regions, and northeast Australia, and eastwards to Tonga and Samoa.

Notes: The juvenile leaves of this species are deep reddish. In some areas (Manus, Sepik, Upper Fly, Milne Bay etc.) these young fronds are harvested and cooked as a vegetable. (See also note under Stenochlaena milnei).

Holttum (1927) notes that the production of fertile fronds may be stimulated by a period of dry weather.

Specimens examinded

West Sepik: Amanab, Yafar, Juillerat 10, 11; Bewani Ranges, Croft 1703
East Sepik: Angoram, Barapidgin village, Leach in NGF 34361; Kabriman village, Leach in NGF 34309; Mindimbit village, Leach in NGF 34276; Tungambit village, Leach in NGF 34243
Madang: Ramu River, Faita village, Hoogland 5054
Morobe: Lae, Red Hill swamp, Hartley 9759; Markham Point, Garrett-Jones in ANU 21150; Butibum River, Hartley 11764; Lake Wamum, Garrett-Jones in ANU 21045; Natter Bay, Croft 398
Western: Balamuk, Asigau W.A.48; Kiunga, Streimann & Katik in NGF 46804; Lake Murray, Pangoa, Gideon et al. In LAE 76186
Gulf: Baimuru, Croft & Vinas in LAE 61297, Croft et al in LAE 61111
Central: Rouna lookout, Rau M.R.4; Brown River, Karoma, Schodde 2527; Sirinumu, Schodde 2986
Milne Bay: Cope Vogel, Menapi, Brass 21781; Fergusson Island, Iamalele, Brass 25993
New Ireland: Lavongai (New Hanover), Mamirum Harbour, Croft in LAE 65536
Manus: Silin station, Croft 1231