Oleandra vulpina, C. Chr, 1937

Hovenkamp, Peter H. & Ho, Boon-Chuan, 2012, A revision of the fern genus Oleandra (Oleandraceae) in Asia, PhytoKeys 11, pp. 1-37 : 18-19

7. Oleandra vulpina Map 5

Oleandra vulpina C.Chr., Dansk Bot. Ark. 9 68. 1937. Type. PAPUA NEW GUINEA. New Guinea: Ledermann 7652 (holotype: BM).

Description.

Rhizome long-creeping, ca. 3 mm thick, not white waxy, sparsely branching, roots with unbranched parts; in cross-section with weakly developed sclerified shealth and few scattered sclerenchyma strands, phyllopodia scattered, 3-6 cm distant, 6-7 mm long. Scales scattered, not covering the rhizome, peltate, to 5 × 0.5 mm, appressed at the base, with a narrow squarrose acumen, dark brown near attachment, lighter towards margin, margin densely set with glands and multicellular hairs terminating in a gland. Fronds monomorphic; stipes with scales as the rhizome but less dense and with short fine glandular hairs; stipe 2-3 mm long, without dark coloration on abaxial side, bearing short fine glandular hairs; lamina linear-lanceolate, 17.5-20 × 3-4 cm wide, base cuneate, apex short caudate, tips up to 1 cm long, margin undulate, weakly cartilaginous, texture papyraceous, all parts with to 0.5 mm long catenate glandular hairs, or with longer, to 1.5 mm, acicular hairs; costa abaxially without dark coloration, with hairs like the stipe and with small scales; veins terminating in a weakly developed hydathode before the margin. Sporangial stalk with glands below the sporangium. Sori in an irregular row 2.5-6 mm from the costa, indusium round-reniform, c. 0.5 mm across, fugacious at very early stage. Spores absent.

Distribution.

New Guinea, at 975 m.

Ecology.

Scandent on trunk of Sago palm in garden, or in forest.

Vernacular name.

Taingelem (Wapi language, Miwaute)

Discussion.

Oleandra vulpina is distinct from Oleandra sibbaldii in the rhizome and costa scales. Rhizome scales are darker in colour with pale-coloured margin, long subulate apices, and margin strongly ciliate with glandular hairs. A similar glandular scale indument is found in the American Oleandra articulata (Sw). C. Presl, but not in the other Southeast Asian species. The costa scales beneath are small and inconspicuous, narrowly lanceolate. In addition, the rhizome of Oleandra vulpina is not glaucous. The indusia are very small and shrivel at a very young stage but are distinct when present and bear numerous setose hairs.

Figures

Map 5. Distribution of Oleandra vulpina (triangles), Oleandra werneri (circles).