Chassalia beamanii 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 : 12-15

Chassalia beamanii T.Y.Yu sp. nov.

urn:lsid:ipni.org:names:77215403-1

Figs 6–7

Diagnosis

Differs from other big-leaved species in having leaves clustered at apex of stem, in infructescences mostly terminal, in fruits significantly obovoid (fruits of most other Asian species of Chassalia are ovoid or round).

Etymology

Named after American botanist, John Homer Beaman (1929–2015), who collected this species and most other specimens of Chassalia from around Mount Kinabalu.

Type

MALAYSIA – Borneo , Sabah • Ranau District, near Poring Hot Springs along trail to tourist canopy walkway; 6°03′ N, 110°42′ E; 9 Aug. 1990; John H. Beaman 10924; holotype: K[ K001129721 ]!; isotype: MSC .

Additional material

MALAYSIA – Borneo , Sabah • Ranau District, Kampung Melangkap Tomis, 3 km dari Melangkap Tomis; 10 Sep. 1995; Lorence Lugas 954; K!, SNP • Kawasan Labi ; 14 Jan. 1996; Lorence Lugas 1676; K!, SNP .

Description

Shrub or small treelet, around 1 m tall, glabrous. Stem terete, hollow, slightly flattened when dry, 4–6(– 8) mm wide; successive nodes flattened at right angles, internode on the flowering branch 1–3 cm long, gradually compressed at apex. Leaves opposite, decussate. Leaf-blades obovate to broadly elliptic, 21– 28 × 7–11 cm, broadest at about middle or above; apex acute to attenuate; base attenuate; midrib slightly raised above, domatia absent; secondary nerves 12–18 on each side of the midrib, prominent above. Petioles flattened, canaliculate, 3–4 × 0.1–0.2 cm, 1 cm long when immature. Stipule not sheathing, broadly flabellate, 5–10 × 8–15 mm, apex broken very easily, base drying deep brown, 5–8 × 8–10 mm, sometimes very small, 3 × 2 mm; margin light brown. Inflorescences compound cymes, 1.5–4 cm long; peduncle 8–20 × 2 mm, rachis and branches 3–15 mm or absent. Bracts 4–9 in each capitulum, 3–6 × 3–4 mm. Flowers not seen. Fruits obovoid, broadest at ¾ from base, 6–7 × 4–6 mm, with 2–3 veins visible on pericarp; pedicel of fruit short, 2–3 mm; calyx tube persistent or broken, 0.5–1 × 1–2 mm, lobes usually broken. Disc persistent, longer than persistent calyx tube, 0.8–1.2 × 0.7–0.8 mm. Pyrenes plano-convex, dorsal surface convex, with two adjacent parallel longitudinal crests, each 0.1 × 0.3 mm, curved, 0.3 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 0.3 × 0.6 mm, with a groove between the edge of endocarp and endocarpal outgrowth 0.2–0.3 mm wide. Raphal opening at base of the endocarpal outgrowth, narrowly ovoid, 0.5 × 0.2 mm, 0.2–0.3 mm from the edge of the pyrene wall, apex with a bony spine, spine triangular, erect, 0.5–0.7 × 0.2–0.3 mm. PGS not detected. Seed light brown, hemi-ellipsoid, slightly crested at central part of dorsal side, 0.3 × 4 mm, endosperm not detected.

Distribution, habitat

Endemic to Borneo. Only known from the Ranau District of Sabah. Lowland forest, alt. 650– 750 m.

Figures

Fig. 6. Chassalia beamanii T.Y.Yu sp. nov.A. Flowering shoot. B. Infructescence. C. Pyrene transection. D. Dry fruit. E. Pyrene ventral surface. From John H. Beaman 10924. Drawn by T.Y. Yu.

Fig. 7. Holotype of Chassalia beamanii T.Y.Yu sp. nov. (John H. Beaman 10924).