Chassalia northiana T.Y.Yu, 2021

Yu, Tian Yi, Turner, Ian M. & Cheek, Martin, 2021, Revision of Chassalia (Rubiaceae-Rubioideae-Palicoureeae) in Borneo, with 14 new species, European Journal of Taxonomy 738, pp. 1-60 : 49-52

Chassalia northiana T.Y.Yu sp. nov.

urn:lsid:ipni.org:names:77215414-1

Figs 28–29

Diagnosis

Differs from Chassalia blumeana Govaerts to which it is most similar, by having inflorescence branches and rachis Ẑ 5 mm, usually 1–5 cm long, bracts of inflorescence branches and rachis usually consist of 2 leaf-like bracts and 2 stipule-like bracts, leaf-like bracts sometimes develop to 3–7 cm long.

Etymology

Named for Marianne North (1830–1890), who included this plant in painting 624 entitled Curious Plants from the Forest of Matang, Sarawak, Borneo (https://images.kew.org/botanical-art/mariannenorth/624-curious-plants-forest-matang-sarawak-5122480.html) which is the first image record of this species, made in the 1860s. It is possibly the earliest record of the genus from Borneo.

Type

MALAYSIA – Borneo, Sarawak • First Division, Kuching, Matang , proposed Matang National Park , Sungai Sendok ; 8 May 1987; Bernard Lee Meng Hock S 53828 ; holotype: K [ K001129725 ]!; isotype: SAR .

Additional material

MALAYSIA – Borneo, Sabah • Ranau, Mininsalu; 22 Sep. 1988; Amin & Prancis SAN 123432 ; K, SAN. – Borneo , Sarawak • Sg. Rayu, Matang Forest Reserve ; 27 Mar. 1988; Munting & Jugah, S 55620 ; K!, SAR • 5 th Division, along Sg. Maisa in Maligan Range, Lawas ; alt. 3400 ft; 13 Mar. 1973; Ilias Paie S 32900 ; K!, SAR • Sri Aman Division, Temawai Berau, Sungai Selepong ; 6 Apr. 1990; Rena, Runi, Rantai et al. S 58511 ; K!, SAR .

Description

Herb, shrub to small tree, 1–2 m tall, glabrous. Stem terete, young parts of stems slightly flattened and canaliculate when dry, internode 3–8 cm × 2–4 mm. Leaf-blades obovate to elliptic, usually broadest at ¼ to ½ length from apex, 12–27 × 4–9 cm, apex acuminate with acumen 1–1.5(–3) cm long, base truncate, midrib slightly raised above from both adaxial and abaxial, secondary nerves 8–14 on each side of the midrib, petioles 1–6 cm long. Stipule flabellate, margin usually broken, sometimes slightly bilobed or incised, 8–14 × 5–14 mm, with standard colleters inside. Inflorescence compound cyme, terminal, usually with rachis and 2 branches, 6–14 cm long in total. Peduncle 4–7.5 cm long, branches and first internode of rachis 1–4 cm long, branches usually 0.5–1 cm shorter than rachis, bracts of branches and first internode of rachis usually 4, separate or sheathed at base, 2 leaf-like bracts 1–1.8 cm × 1.5–2 mm, sometimes growing larger than young but not fully developed leaves 3–7 × 1.5–2 cm, 2 stipule-like bracts 5–8 × 5–8 mm, rachis and branches sometimes with second branches and second internode of rachis 2–10 mm long, capitular bracts 8–10 × 2–5 mm. Flowers sessile, 15–18 mm long, corolla tube lower part 0.6–1 mm wide, upper part 2–2.5 mm wide, mouth 3.5–4 mm wide, corolla lobes usually 5, 3 × 2.5 mm, stamens 2.3–2.5 mm long, inserted 1 mm from corolla mouth, inside corolla tube a band of hairs 0.7 mm long at base of stamens, hairs erect, colourless, 0.1–0.2 mm long; stigma bilobed, each lobe round, 0.5 mm in diameter; disc 1.2 × 1.2 mm. Hypanthium 4 × 2 mm, calyx tube 1 × 4 mm with 5 lobes 0.1 × 0.5 mm. Fruit black or deep brown when dry, blue when ripe, ellipsoid to round, 7 × 6 × 6 mm, calyx persistent, not accrescent, 0.5 × 2 mm, disc persistent, not accrescent, 1.2 × 1.2 mm. Pyrene plano-convex, 7 × 5.5–6 × 2–3 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 × 0.2 mm. PGS not detected. Seed light brown, hemi-ellipsoid, 5 × 6 mm, longitudinally slightly crested at midline of dorsal surface, endosperm not detected.

Distribution, habitat

Borneo: Malaysia, from central Sabah to west Sarawak. Alluvial forest, stream banks, Kerangas forest. Lowland to montane forest, alt. 200–1000 m.

Remarks

This species is one of the most widespread of the Bornean ‘involucrate’ species.

Figures

Fig. 28. Chassalia northiana T.Y.Yu sp. nov. A. Flowering shoot. B. Infructescences. C. Flower. D. Longitudinal view of corolla in bud showing stamens, band of hairs, stigma, style, disc, calyx and hypanthium. E. Dry fruit. F. Pyrene ventral surface. A, C–D from Bernard Lee Meng Hock S 53828; B, E–F from Munting & Jugah S 55620. Drawn by T.Y. Yu.

Fig. 29. Holotype of Chassalia northiana T.Y.Yu sp. nov. (Bernard Lee Meng Hock S 53828).