Chassalia atropurpurea T.Y.Yu sp. nov. urn:lsid:ipni.org:names:77215402-1 Figs 4–5 Diagnosis Differs from all other species of Chassalia in Borneo in the stem, petioles, abaxial venation of leaves, peduncles and fruits being blackish purple, both when dried and living (field notes); flowers cream white flushed purple-black; stipule long, elliptic; inflorescence well-developed, peduncle long, bracts of tertiary peduncle usually long, lanceolate. Etymology The epithet reflects the blackish purple coloration of stem, petioles, abaxial venation of leaves, peduncles and fruits which is distinct compared to all other Bornean species of Chassalia. Type MALAYSIA – Borneo, Sarawak • 2 nd Division, Lubok Antu District, Lanjak-Entimau P.F., Bukit Lanjak; 14 Mar. 1974; Paul Chai S 33830; holotype: K[K001129719]![K001129720]! (2 sheets 1 specimen); isotypes: L, KEP[KEP271656]! [KEP271657]! (2 sheets 1 specimen), MO, SAN. Additional material MALAYSIA – Borneo, Sarawak • 7 th Division, Ulu Sg. Kapit, Summit of Bukit Goram; 28 Feb. 1975; Paul Chai S 36121; K!, L, KEP, MO, SAN • Sri Aman Division, Ulu Batang Ai, Bukit Lanjak; alt. 1350 m; 6 Mar. 1994; Yii Puan Ching et al. S 67509; K!, KEP, L, SAN • 2 nd Division, Bukit Bangai, Ulu Lemanak; alt. 915 m; 26 Oct. 1961; S. Collenette 842; K!. Description Shrub to small treelet, 0.8–1.5 m tall, glabrous. Stem blackish purple, terete, not hollow. Internodes deeply canaliculate, (1.5–) 3.5–7.5 cm long. Leaf-blades narrowly elliptic to lanceolate, 9–16 × 1.5–4 cm, apex acuminate, acumen 0.5–1.3 cm long, base cuneate to attenuate, first pair of leaves from apex sometimes very small, 1–3 cm × 3–5 mm. Petiole blackish purple, slightly flattened, 0.9–1.5 cm long. Midrib and secondary veins slightly raised both abaxially and adaxially, secondary veins 8–12 on each side of the midrib and blackish purple abaxially, leaf-blade sometimes slightly impressed around secondary veins, tertiary veins not visible. Stipule elliptic to trapezoidal, 2–12 × 3–9 mm, broken stipules from lower nodes sometimes slightly bilobed. Inflorescences compound cymes, usually well-developed, peduncle canaliculate, (1.5–) 3.5–6 cm long blackish purple, bracts of first internode of rachis and first branches elliptic, 4–5 × 1.5–2 mm, first internode of rachis and first branches canaliculate, (0.5–) 1.5–6 cm long, bract of second internode of rachis and second branches ovate, 3 × 3 mm, second internode of rachis and second branches 1–2 cm long. Bracts of capitulum 4, 2 × 1 mm. Flowers ca 10 in each capitulum, more or less sessile, hypanthium ca 1 mm long, calyx tube ca 0.5 mm long, lobes triangular, ca 0.2 mm long, corolla white flushed purple, 11–12 mm long at largest point in bud before corolla lobes separate, lower tube straight, ca 5 mm long, 0.5–0.8 mm diameter, distal portion inflated, turbinate with top domed, ca 6 mm long, ca 3 mm maximum diameter, corolla lobes oblong-ovate 2–3 × 2 mm, apex apiculate with a thickened tip. Stamens 2 × 0.4 mm, 2 mm from apex of corolla tube, 6.5 mm from base of corolla tube, anthers with an apical connective appendage 1 mm long, filaments very short, less than 0.1 mm long, band of hairs at base of stamens 1 mm wide, each hair around 0.2 mm long. Style 12 mm long, exserted about 2 mm from mouth of corolla, stigma bilobed, each lobe orbiculate, 0.8 mm diameter. Disc cylindric, 0.8 × 0.8 mm. Fruits ellipsoid, 6 × 5.5 × 4.5 mm, dark purple to iridescent blue, calyx persistent, not accrescent, 2 × 2 mm, disc persistent, not accrescent, 0.5 × 1.2 mm. Pyrene plano-convex, 8–9 × 5.5 × 2.5–3 mm, dorsal surface convex, with two adjacent parallel longitudinal crests, 0.4 mm wide, 0.25 mm apart along their length, forming a longitudinal groove from apex to base between the two crests; ventral surface concave, central part slightly elevated, margin with an endocarpal outgrowth 1 mm wide, with a groove between the edge of endocarp and endocarpal outgrowth 0.5 mm wide. Raphal opening at base of the endocarpal outgrowth, round, 0.4 mm wide, 0.2–0.3 mm from the edge of the pyrene wall, apex with a bony spine, spine triangular, erect, 0.8 mm × 0.2 mm. PGS not detected. Seed light brown, hemi-ellipsoid, 0.5 mm × 6 mm, longitudinally slightly crested at midline of dorsal surface, endosperm not detected. Distribution, habitat Borneo: Sarawak. High-altitude (910–1350 m a.s.l.) summit montane forest, open places.

Published as part of Yu, Tian Yi, Turner, Ian M. & Cheek, Martin, 2021, Revision of Chassalia (Rubiaceae-Rubioideae-Palicoureeae) in Borneo, with 14 new species, pp. 1-60 in European Journal of Taxonomy 738 on pages 9-12, DOI: 10.5852/ejt.2021.738.1261, http://zenodo.org/record/4594541