Chassalia muscicola 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 : 46-49

Chassalia muscicola T.Y.Yu sp. nov.

urn:lsid:ipni.org:names:77215413-1

Figs 26–27

Diagnosis

This is the smallest of all Bornean species of Chassalia , differing from all other species in being just 25–30 cm tall (other species are at least 40 cm tall, and usually a minimum of 1 m tall), in the obovate leaves just 5.5–7.5 cm long (in other species they exceed 10 cm long and may attain 48 cm long), in the apex of leaves obtuse (acute or acuminate in most other species), in having large white fruits 8 × 7 × 7 mm (all other species have blue or purple or black fruits), in having a large bony spine 2 × 1 × 0.5 mm on the ventral surface of the pyrene.

Etymology

The epithet alludes to summit moss forest where it has been collected.

Type

MALAYSIA – Borneo, Sarawak • 1 st Div., Simunjan, Serian /S’ggang Rd., Gunong Gaharu 70 th Mile ; alt. 800 m; 8 Oct. 1974; Ilias & Azahari S 35671 ; holotype: K [ K001129718 ]!; isotypes: L, KEP, SAR .

Additional material

MALAYSIA – Borneo, Sarawak • 2 nd Div., Gunong Aping ; alt. 900 m; 13 Jul. 1961; S. Collenette 742; K!, SAN .

Description

Herb, 25–30 cm tall, glabrous, almost half of the plant growing among mosses. Stem 1–2 mm wide, usually producing adventitious roots 1–8cm below lowest internode, internodes 1.8–3.5 cm long, lower internodes terete, upper internodes drying flat, slightly canaliculate. Leaf-blades narrowly obovate to oblanceolate, coriaceous, adaxially dark green, abaxially light yellowish-green, (2.5–)4–6.5 × 1.3– 1.8 cm; apex obtuse, base attenuate; midrib slightly raised both adaxially and abaxially, secondary nerves 7–12 on each side, tertiary nerves not visible; petiole short, 5–10 mm long. Stipule flabellate, 5–7 × 4–5 mm. Inflorescences short, 4.5 cm long, peduncle 3.5 cm × 0.8 mm, broadening near apex to 2 mm wide, bracts of first internode of rachis and first branches 4, broadly elliptic, 4.5 × 2–3.5 mm; first internode of rachis and first branches very short to absent, usually less than 1 mm; bracts of capitulum 4–6 or more, 4–4.5 × 1–4.5 mm, with crystal bodies on each rachis bract and capitulum bract. Flowers 6–12 in each capitulum, open flowers not seen; hypanthium 1.5–2 mm long, calyx tube 0.7 mm long, apex slightly curved. Corolla white, glabrous, 1–1.8 cm long in bud, tube slightly broadened at apex, 5 mm long before opening, 1 mm wide at base, apex 2.5–3 mm wide, band of hairs 1 mm wide, at base of stamens 1–2 mm from mouth of corolla tube, hairs erect, colourless, 0.1–0.2 mm long; open flower not seen. Stamens 1 × 0.5 mm, slightly concave, base bifurcate, inserted ca 1.5 mm from mouth of corolla, filaments very short to absent. Stigma bilobed, lobes orbiculate, 0.6 mm diameter. Disc cylindric, 0.4 mm long, 0.7 mm wide, apex flat. Fruits sessile, ellipsoid, 7–8 × 7 × 7 mm, pure white; calyx persistent, not accrescent, 1 × 2 mm, disc persistent, not accrescent, 0.5 × 1 mm. Pyrenes plano-convex, 7–8 × 6–7 × 4 mm, dorsal surface convex, with two adjacent parallel longitudinal crests, 1 mm wide, 1 mm high, 0.5 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 0.2 mm wide, with a groove between the edge of endocarp and endocarpal outgrowth 0.2 mm wide. Raphal opening at base of the endocarpal outgrowth, round, 0.5 mm wide, 0.2–0.3 mm from the edge of the pyrene wall, apex with a bony spine, flabellate, 2 × 1 × 0.5 mm. PGS not detected. Seed light brown, hemi-ellipsoid, 6 × 0.5 mm, longitudinally slightly crested at midline of dorsal surface, endosperm not detected.

Distribution, habitat

Borneo: Malaysia, Sarawak, Gunung Gaharu (1 st Division) and Gunung Aping (2 nd Division), summit of mountain, moss forest, alt. 800– 900 m.

Figures

Fig. 26. Chassalia muscicola T.Y.Yu sp. nov. A. Habit. B. Infructescence. C. Hypanthium, calyx and disc of a flower. D. Inflorescence. E. Pyrene ventral surface. A–B, E from Ilias & Azahari S 35671; C–D from S. Collenette 742. Drawn by T.Y. Yu.

Fig. 27. Holotype of Chassalia muscicola T.Y.Yu sp. nov. (Ilias & Azahari S 35671).