Table 1.

The Sabah Christisonia compared with five other taxa

	Sabah Christisonia	C. scortechinii	C. siamensis	C. sinensis	C. calcarata	C. hookeri
Pedicel	Short-thick, ca. 1 cm long	Short-thick, ca. 1 cm long	Short-thick, ca. 1 cm long	Short-thick, ca. 1 cm long	Slender, 2–3.5 cm long	Short-thick, ca. 1 cm long
Calyx colour	White	White to purplish	White, yellowish to dark purple	White	Pale yellow	Violet
Calyx surface	Glabrous	Glabrous	Glabrous	Glabrous	Glabrous	Glabrousa
Calyx lobes/teeth	2–4 (–5)	2–4 (–5)	(2–) 3 (–4)	(2–) 3–4 (–5)	5	(4–) 5
Enclosure of corolla tube by calyx (herbarium material)	About half	Less than half	Less than half	About half	Less than half, to half	About half
Enclosure of corolla tube by calyx (fresh material)	About a quarter	A quarter to a third	A third to half	A quarter to a third	A quarter to a third	?
Corolla colour	White	White to tinged with violet	White tinged with violet	White	White	White with violet seams
Corolla pubescence	Glabrous	Glabrous	Glabrous	Glabrous	Tube outer surface and both sides of lobes white-pubescent	Glabrous
Corolla lobe & throat colour	White, with yellow-orange patch from base of lip down to inside the tube	White, with dark yellow patch from base of lip down to inside the tube	Bluish to violet, with yellow patch from base of lip down to inside the tube	White to slightly lilac, with yellow-orange patch from base of lip down to inside the tube	White to greyish or bluish, bright yellow patch on all lobes to down inside the tube	?
Hairs at point of attachment of anthers	Glabrous	Glabrous	Distinct hair tuft obstructing corolla throat	Glabrous	Sparse scattered short hairs on filaments	Glabrous
Anther appendage, dorsal side	With short acute projection	With “projecting acute posterior process” (Prain 1904)	With short acute projection	With short acute projection	With a slender spur-like projection	Rounded, without acute projection
Stigma	Peltate	Peltate	Peltate	Peltate	Bilobed	Bilobed
Known distribution	N Borneo (Sabah)	Peninsular Malaysia, Thailand, Vietnamb	Thailand (N NE, SW), India (Nagaland)	SW and SE China	India, Pakistan	India
Habitat	Montane sites over 2000 m	Montane sites ca. 650–1700 m	Mixed deciduous forest at 300–800 m	Montane forest, 1500–2000 m	Montane sites	Montane sites

^aNot pubescent as stated in Benniamin et al. (2012)

^bMaterial from Thailand (N, NE, SE, Peninsular, from ca. 1200–1655 m) and a more northerly latitude in C Vietnam (642 m) placed in C. scortechinii by Parnell et al. (2014)