Polyosma torricellensis Schltr.

Paul, O. K., Conn, B. J. & Henwood, M. J., 2024, Taxonomic review of Polyosma (Escalloniaceae) in Papuasia, Blumea 69, pp. 54-88 : 86

32. Polyosma torricellensis Schltr.

Polyosma torricellensis Schltr. (1915) 130. — Lectotype (designated here): R. Schlechter 20319 (lecto LY [ LY218962 ]), Papua New Guinea, West Sepik, ‘ Torricelli-Geb [irges]’, 12 Sept. 1909.

Polyosma torricellensis Schltr. var. pittosporoides Schltr.(1915) 131, syn.nov. — Lectotype (designated here): R. Schlechter 20166 (lecto P [ P709677 ]; isolecto LY [ LY218963 , LY218964 ]), Papua New Guinea, West Sepik, ‘ Torricelli-Geb [irges]’, 12 Sept. 1909 (see Typification below).

Typification — The type collections of P. torricellensis and P. torricellensis var. pittosporoides held at B are here regarded as destroyed ( Merrill 1943, Hiepko 1978, 1987). Therefore, lectotypes are here selected for both taxa. Although type material of P. torricellensis (R. Schlechter 20319) was expected to be held at P, none were located. Therefore, material held at LY, based on photographs, was selected. Type material of P. torricellensis var. pittosporoides held at P was selected as the lectotype of this variety. The photograph of R. Schlechter 20319 ( P. torricellensis ) and the herbarium material of R. Schlechter 20166 ( P. torricellensis var. pittosporoides ) are in full agreement with the protologue of each respective taxon.

Canopy tree, 10–20 m tall. Branchlets minutely pubescent when young, soon glabrous, brown. Leaves glabrous; petiole unknown (see notes below); lamina elliptic to narrowly elliptic, 9–15 by 1.5–3.5 cm, drying brown on both surfaces; base cuneate, margin distally shortly dentate, apex acuminate; secondary veins c. 8 on each side and at an angle greater than 45° (initially almost at 90°) from midrib, looping some distance from margin onto the next secondary vein; tertiary veins weakly percurrent, glabrous, not prominent on abaxial surface. Inflorescence racemose, terminal, suberect, 5 – 6 cm long, 6–20-flowered (indumentum not known); bracteoles not known. Calyx tooth-like, small. Corolla buds tubular, c. 10 mm long, yellow. Fruits not seen.

Distribution — Only known by type collections (Schlechter 20166 & 20319), West Sepik, Papua New Guinea.

Habitat & Ecology — Recorded as occurring in lowland forest at an elevation of ‘800 m’ ( Schlechter 1915).

Conservation status — Since the taxonomic status of this species is not well known, it is not possible to evaluate its conservation status.

Notes — 1. Since the Schlechter 20319 (Type) was not available for study, we have relied on the protologue and the type specimen of P. torricellensis var. pittosporoides (Schlechter 20166) to understand Schlechter’s species concept. Schlechter described the petioles (‘Stielchen’) of P. torricellensis as 4 mm long ( Schlechter 1915: 128 – in the identification key). Since the lamina of the leaves on Schlechter 20166 (P) are broken, there are no petioles available for measurement. Our lack of understanding of the morphological variation within this species and, hence, its taxonomic status, results from the lack of known populations and herbarium specimens.

2. Although P. torricellensis var. pittosporoides is recorded as having slightly wider leaves than the typical variety (up to 4.5 cm wide vs 1.5–3 cm wide, respectively), it is here regarded as not sufficiently different to warrant taxonomic recognition, being a higher elevation broader-leaved variant of lower elevation plants of the nominant species.