Oleandra sibbaldii, Grev, 1848

Hovenkamp, Peter H. & Ho, Boon-Chuan, 2012, A revision of the fern genus Oleandra (Oleandraceae) in Asia, PhytoKeys 11, pp. 1-37 : 16-17

5. Oleandra sibbaldii Map 4

Oleandra sibbaldii Grev., Ann.and Mag.Nat.Hist.Ser.2 1: 327. 1848. Copel., Bull. Bernice P. Bishop Mus. 93: 61. 1932. Philipp. J. Sci. 73: 346. 1940. C.Chr., Bull. Bernice P. Bishop Mus. 177 47. 1943. Copel., Fern Flora of the Philippines: 183. 1958. Brownlie, The Pteridophyte Flora of Fiji: 157. 1977. M.Kato, J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 14: 239. 1989. R.M.Tryon, Rhodora 102: 436, fig. 7. 2001. Oleandra cumingii var. sibbaldii Baker, Syn. Fil. (Hooker & Baker): 303. 1868. Type: FRENCH POLYNESIA. Tahiti: Sibbald s.n. (holotype: E, barcode E00417634, not seen).

Oleandra tricholepis Kunze, Kunze, Bot. Zeitung (Berlin) 9: 349. 1851. Type. INDONESIA. Bornea: Hupe s.n. (holotype: LZ, probably destroyed).

Oleandra whitmeei Baker, J. Bot. 5: 11. 1876. (" whitmei "). Oleandra whitmeei Copel., Polypod. Phil. Isl.: 49. 1905. Copel., Bull. Bernice P. Bishop Mus. 59 87. 1929. Type. SAMOA. Savai’i: Whitmee & Powell s.n. (holotype: K).

Oleandra gracilis Copel., Univ. Calif. Publ. Bot. 12: 397, pl. 52b. 1931. Copel.Philipp. J. Sci. 73: 347. 1940. Type: PAPUA NEW GUINEA. New Guinea: Keysser 74 (holotype: UC).

Oleandra crassipes Copel., Philipp. J. Sci. 73: 347, Pl. 2. 1940. Type: INDONESIA. New Guinea: Bernhard camp, Brass 12109 (holotype: UC; isotypes: BO, L).

Description.

Rhizome long-creeping or pendulous, sparsely branching, 1.5-4.5 mm thick, very strongly white waxy, in cross-section without or with few scattered sclerified strands, phyllopodia scattered, (0.3-)0.8-4.0(-5.7) cm long, roots with distinct unbranched parts. Scales deciduous, exposing the rhizome in older parts, peltate, (3-)5-15(-18) × (0.3-)0.4-0.9(-1.2) mm, usually widest above the attachment, squarrose, reddish brown, margin entire or more or less densely set with sessile glands, acumen attenuated, long filiform apex. Fronds monomorphic; stipe (0.3-)0.5-3.5(-4.5) cm long, often with dark coloration on abaxial side; lamina to (4.5-)15-40(-58) × 1-4(-6) cm, widest in middle part, base attenuate to cuneate, sometimes rounded, rarely truncate, sometimes asymmetric, apex acuminate or up to 3 cm caudate, texture membranous to coriaceous, both sides sparsely to densely set with catenate hairs to c. 0.5 mm long; costa on lower surface often with dark-coloration, on both surfaces with scales, scales on lower surface often abundant, to 6(-11) × 1(-1.2) mm, pale to dark brown, on upper surface scarce, inconspicuous. Sori inframedial, leaving a distinct 1-4 mm wide sterile zone between costa and soral zone, sometimes as much as 12 mm from costa, indusium firm, to 1 mm wide, hairy. Sporangial stalk with glands below the sporangium. Spores with an irregular mesh-like network of up to 10 µm high folds, finely papillose with spinules up to ca. 4 × 1 μm, perispore baculate, outer layer much perforated.

Distribution.

Eastern Malesia to Pacific Islands. Malaysia: Sabah, Sarawak, Philippines: Mindanao; Indonesia: Sulawesi; Moluccas, Papua; Papua New Guinea; Solomon islands; Vanuatu; Tahiti and Marquesas: Hiva Oa, Nuku Hiva, Tahuata, Ua Huka and Ua Pou; Western Samoa: Savaii; Fiji.

Ecology.

Epiphytic, epilithic, or less commonly terrestrial (most often at elevations over 1500m), commonly collected from mossy forests, climbing or sprawling among bryophytes and other epiphytes, or pendulous from mossy tree branches, to 600 m (Marquesas and Tahiti); or from 1000 to 3000 m (elsewhere).

Discussion.

Oleandra sibbaldii is common on New Guinea, but appears to be much sparser towards the periphery of the distribution area.

The dark colour on the abaxial surface of the costa is often very conspicuous, extending on the stipe, thus rendering the stipe conspicuously bicolorous.

Figures

Map 4. Distribution of Oleandra sibbaldii.