Squamellaria guppyana (Becc.) Chomicki

53. Squamellaria guppyana (Becc.) Chomicki View in CoL — Fig. 56 View Fig

Squamellaria guppyana (Becc.) Chomicki in Chomicki & S.S.Renner (2016) 20; Hydnophytum guppyanum Becc. (1885) 133, t. 40 partim.; H.B.Guppy (1887) 297; Rech. (1913) 612; Merr. & L.M.Perry (1945) 25. — Type: Guppy s.n. partim. (lecto FI barcode FI008898; iso K, L), Solomon Islands, Shortland Island, Mar. 1884.

Hydnophytum hahlii Rech. (1912) 186; (1913) 612, t. 2, f. 3a; Merr. & L.M. Perry (1945) 25. — Type: Rechinger 3552 (holo W), Bougainville, Djup, syn. nov.

Hydnophytum longipes Merr. & L.M.Perry (1945) 23. — Type: Kajewski 1571 (lectotype selected here A; iso BRI), Bougainville, Kieta, 21 Mar. 1930, syn. nov.

Tuber oblong-ovoid; 30 by 15 cm; pendent to clasping (on vertical trunks); fawn to deep brown in colour. Entrance holes numerous; 0.2–0.4 cm diam; arranged in concentric circles about long axis of tuber; in some tubers occluded by corky plugs; often with 1 or more large, funnel-like openings along side of tuber to 2 by 5 cm. Roots numerous on substrate side of tuber, and around base of stem. Cavities pale to dark-walled, some chambers with root-like warts in clusters, 1–2 mm long. Stems several, to 3 m; little branched. Internodes 1–13 cm, with a prominent ridge descending from below stipule on each side of stem. Bark grey, green towards apex. Leaves lax, drying thin. Lamina lanceolate, ovate or obovate; 5.5 by 2 to 20 by 11 cm; apex blunt to acute; base attenuate; dark green, somewhat brittle. Petiole 0–1 cm, usually winged throughout; stipules triangular, acuminate to 0.3 cm. Inflorescence solitary, initially terminal, becoming axillary; pseudodichotomously branched; primary peduncle to 6 by 0.5 cm, winged, with 2(–4) secondary, dichotomously branching axes, these up to 10 cm in length; main axis continuing with up to 2 further branch points. Flowers [27] heterostylous. Calyx 1.5 mm, as long as disc. Corolla tube 3 mm, widest near base, with a ring of hairs in corolla mouth; lobes to 2.5 mm, fully reflexed in open flower, uncus 0.5 mm. Short-styled flowers with anthers to 1.5 mm; exserted from corolla mouth; filaments to 2 mm; pollen 37–47 (43) μm, wall 3.75 μm thick, brochi 1 μm, pores 9–12 μm across, vesicles very small; style 2 mm, stigma within corolla tube, 2-lobed. Long-styled flowers with anthers to 1 mm; below corolla mouth, filaments to 0.5 mm; pollen 31–41 (37) μm; style 3.5 mm, stigma exserted. Fruit obovoid, 8 by 4 mm, with prominent calyx and disc remains. Pyrenes obovoid to oblong; to 5.5 by 2.5 cm; flattened dorsoventrally; apically rounded; base rounded to tapered, abaxial face with a longitudinal ridge.

Ecology & Habitat — Common throughout the Solomon Islands in mangrove swamps, riverside forest etc., sea level to 600 m. Often ant-inhabited, by a extensive range of ant species, but some cavities capable of collecting rainwater.

Distribution — Papua New Guinea (Bougainville),Solomon Islands (Shortland, Choiseul, New Georgia group, Kolombangara, Santa Isabel, Guadalcanal and San Cristobal).

Conservation status — Least Concern (LC). This species is found on seven islands with a geographical spread of 700 km. Other information: georeferenced collections 20, AOO 80 km 2 (using a cell width of 2 km), EOO 62 100 km 2.

Notes — Beccari described this species from a Guppy collection, which is unfortunately a mixture of two species – the tuber collected by Guppy, and illustrated by Beccari (1885: t. 40: 1) is that of S. kajewskii [54]. All other material is of S. guppyana , and there is no confusion in the original diagnosis.

The inflorescence is remarkable in its resemblance to that of a Psychotria species. It arises terminally, is solitary, and has a pseudodichotomously branching peduncle. Beccari was convinced that the specimens he examined must have lost the opposite inflorescence of the pair, which would otherwise, as he pointed out, have been identical to a Psychotria (Beccari 1885: 135) . He was anxious enough to have even got the draftsperson to tentatively add the base of the ‘missing’ inflorescence in the plate (Beccari 1885: t. 40: 2). Squamellaria kajewskii shares this inflorescence structure, although in this latter species the size and degree of branching is much reduced.

The corky plugs that occlude the entrance holes in some tubers are unique in the subtribe. It appears that this makes the tuber cavities water-tight in some individuals, and may allow a tuber not occupied by an ant-colony to act as a water-collecting organ. The tuber-cavity structure comprises encircling chambers that girdle the tuber, with rings of entrance holes that form encircling lines on the tuber surface. This morphology is identical to that seen in the Fijian Squamellaria species and lends weight to the decision by Chomicki & Renner (2016) to place this species in the latter genus.