Chassalia calamus T.Y.Yu, 2021

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 : 16-19

publication ID


persistent identifier

treatment provided by


scientific name

Chassalia calamus T.Y.Yu

sp. nov.

Chassalia calamus T.Y.Yu sp. nov.

Figs 8–9 View Fig View Fig


Differs from other species in having a strong and thick, but hollow, stem 5–12 mm diameter (vs stem solid, ca 3–5 mm diameter); leaves large 17–33 × 5.5–12 cm (in most species except C. atropurpurea sp. nov. and C. involucrata sp. nov. not reaching these dimensions); inflorescence usually very short with peduncle very short or absent, (<0.1–) 0.5–3.5 cm (in other species usually exceeding 3.5 cm long); secondary peduncle usually very short to absent making the inflorescence highly compact.


The epithet, treated as a noun in apposition, is derived from the Latin ʻ calamus ʼ, a reed or more generally a hollow-stemmed plant. The name refers to the hollow stem, unusual in Bornean species of Chassalia .


MALAYSIA – Borneo , Sabah • Nabawan, Sungai Millian , along stream-side; 18 Nov. 1986; Asik Mantor SAN 118683; holotype: K[ K001129723 ]!; isotype: SAN .

Additional material

MALAYSIA – Borneo , Sabah • Keningau, Crocker range area, mile 16, Kimanis Road; 23 Aug. 1986; Sumbing Jimpin SAN 120566 View Materials ; K!, KEP!, SAN Tambunan, Sunsuron Km 54 Jalan Tambunan/ Penampang; alt. 1400 m; 24 Aug. 1989; Fidilis. K. SAN 127894 View Materials ; K!, SAN Ranau, Ulu Tungud Forest Reserve , Gunung Monkobo Expedition ; 5°52′45″ N, 116°55′28″ E; alt. 343 m; Saw L.G. SAN 146079 View Materials ; K!, SAN GoogleMaps Tambunan, Rafflesia Information Centre , Hill Dipterocarp Forest ; 2 Sep. 2001; J.T. Pereira et al. JTP 845; K!, SAN Pandewan, Sungai Pamentarian ; 25 Feb. 1987; Sumbing Jimpin SAN 120057 View Materials ; K!, SAN .


Herb, shrub to small treelet, (0.5–) 1–1.5 m tall, glabrous. Stem terete, flattened and slightly canaliculate, or sometimes deeply canaliculate, hollow. Lower internodes 3–6 × 0.5–1.2 cm, surface usually covered by pustules, internode of flowering stems shorter, 1–2.5 × 0.3–0.8 cm. Leave-blades elliptic to broadly lanceolate, very large, 17–33 × 5.5–12 cm, midrib raised both adaxially and abaxially, secondary veins 14–18 on each side, petiole flat, canaliculate, (0.5–) 1.5–5 cm. Stipule large, not sheathing, broadly flabellate, 0.8–1.2 × 0.8–2 cm, apex usually irregular. Inflorescence a compound cyme, peduncle very short to absent, (<0.1–) 0.5–3.5 cm, rachis and branches usually very short to absent, (<0.1–) 1.5 cm. Bracts 8–10 in each capitulum, pale green, 7–8 × 3–4 mm. Flowers 14–20 in each capitulum, pedicel short or absent, hypanthium ellipsoid, 1.5 × 1.5–2 mm, calyx tube slightly curved, 1.5–1.8 × 0.5 mm in total, corolla whitish green, cream-white or yellowish white, 10–12 × 0.5 mm, corolla tube 0.5 mm wide at base, broadening in distal third to 2.5 mm wide; corolla lobes triangular, 2–2.5 × 1.5 mm. Disc cylindric, 0.8 × 0.5 mm. Stamens 2.2 × 0.2 mm, anthers placed at the mouth of corolla, filament insertion 8 mm from base of corolla, filament very short, less than 0.1 mm long, band of hairs 0.5–1 mm wide, at base of stamens 8 mm from mouth of corolla tube, hairs erect, colourless, 0.1–0.2 mm long. Style 1.5 cm long. Fruits ellipsoid, 5–8 × 4–5 × 3.5–4 mm, pedicel of fruit persistent, not accrescent or slightly accrescent, 3–4 mm long. Pyrenes plano-convex, dorsal surface convex, with two adjacent parallel longitudinal crests, each 0.1 × 0.25 mm, curved, 0.4 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 0.7 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, 0.2 mm in diameter, 0.2–0.3 mm from the edge of the pyrene wall, apex with a bony spine, spine triangular, erect, 0.5 × 0.2 mm. PGS not detected. Seeds light brown, hemi-ellipsoid, slightly crested at central part of dorsal side, 4.5 × 0.7 mm.

Distribution, habitat

Borneo: Malaysia, Sabah, around Ranau and Tambunan. Hill forest, stream valley, rocky moist slopes, alt. 125–1300 m.


Forest Research Institute Malaysia


Forest Research Centre


Royal Botanic Gardens