Spiradiclis coccinea H. S. Lo

Tong, Yi-Hua, Xia, Nian-He, Wu, Lei & Vu, Tien Chinh, 2020, Critical notes on Spiradiclis purpureocaerulea H. S. Lo (Rubiaceae) from Vietnam, Adansonia (3) 42 (19), pp. 291-296 : 292-296

Spiradiclis coccinea H. S. Lo

( Figs 1D-F ; 3 )

Bulletin of Botanical Research, Harbin 6 (4): 38 (1986).

S. purpureocaerulea auct. non H. S. Lo, Lee et al., Korean Journal of Agricultural Science 46 (3): 647, fig. 3 (2019).

TYPE SPECIMEN. — China. Guangxi: Longzhou County, Wulian Town, Banbi Village , dense forest, on rocks, 4.VIII. 1957, S. H. Chun 13475 (holo-, IBSC [ IBSC 0510628 ]!; iso-, IBK [ IBK 00191517 ]!) SPECIMEN DATA. — Vietnam. Ninh Binh: Nho Quan District, Forest Control Point , 20°16’28”N, 105°40’57”E, alt. 400 m, 17. VI. 2014, N. S. Khang 708 ( HN). — Ha Nam: Kien Khe District , 20°29’12”N, 105°52’9”E, alt. 198 m, on limestone hills, 3. VI. 2019, N. H. Xia et al. TYH-2163 ( IBSC) .

DESCRIPTION

Perennial herbs, to 20 cm tall; stems erect, glabrous or subglabrous. Leaves shortly petiolate; petioles 1-2 mm long; blade narrowly elliptic-oblong or elliptic-oblong, 4-8 × 1.3-3 cm, drying papery, glabrous on both surfaces, adaxially dark green, abaxially pale green, apex obtuse to acute, base cuneate, secondary veins 5-9 on each side of the midrib; stipules triangular, 3-5 mm long, 2-3 mm wide at base, apex acute to long acuminate, 0.5-1.5 mm long. Inflorescence congested-cymose, terminal, 8-12-flowered or more, glabrous; peduncle usually 0.5-5 mm long, glabrous; bracts subulate-triangular, 0.5-1.5 mm long, glabrous on both surfaces. Flowers distylous.Calyx glabrescent; hypanthium portion obconic, 1.2-2 mm long; lobes narrowly lanceolate, 1.7-3 mm long. Corolla dark red or purple red, slenderly salverform, glabrous or puberulent outside; tube 1.5- 2.4 cm; lobes broadly ovate to suborbicular, 4.5-6 mm long, apex acute; stamens 5; stigma bilobed; ovary 2-celled, ovules numerous in each cell on peltate axile placentas attached to middle of septum. Long-styled flowers: corolla tube inside with pilose ring above stamens; filaments 1.5-2.5 mm long, adnate to the base of the corolla tube; anthers linear, c. 3 mm long, positioned near the base of the corolla tube; style 1.2-1.5 mm long, glabrous; stigmas positioned a little below the throat of the corolla tube, lobes linear-oblong, c. 2.4 mm long. Shortstyled flowers: corolla tube inside with dense pubescence near the base; filaments 9-13 mm long, adnate to the corolla tube; anthers linear, c. 3 mm long, positioned at 2/3 of the corolla tube; style c. 2 mm long, glabrous; stigmas included near the base of the corolla tube; lobes lanceolate, c. 1.8 mm long. Capsules subglobose, 4-4.5 mm in diam., glabrous, opening into 4 valves. Flowering June-August, fruiting August.

REMARKS

Spiradiclis coccinea is morphologically similar to S.purpureocaerulea by thecongested-cymose inflorescences,short peduncles, slenderly salverform corollas and subglobose capsules, but differs from the latter mainly by having erect stems (vs ascending), most plant parts glabrous or subglabrous (vs densely pubescent), leaf blades narrowly elliptic-oblong or elliptic-oblong(vs ovate to ovate-elliptic) and calyx lobes 1.7-3 mm long (vs 3.5-4.5 mm long) ( Lo 1986). Currently, there are five species of Spiradiclis distributed in northern Vietnam ( Lo 1999; Hô 2000; Lee et al. 2019). Among them, Spiradiclis coccinea , S. leptobotrya and S. purpureocaerulea are restricted to limestone karst areas and usually occur at elevations of 300-600 m, while S. caespitosa and S. hainanensis grow on slightly acidic soil at elevations of 2500-2900 m and 0-1200 m, respectively. Additionally, the flowering time of the genus in Vietnam is concentrated in May ( S. hainanensis ), July ( S. coccinea ), September ( S.caespitosa and S.purpureocaerulea ) and December ( S. leptobotrya ). A key to the five species of Spiradiclis in Vietnam is provided below.

Figures

FIG. 1. — A-C, Spiradiclis purpureocaerulea H. S. Lo: A, habit; B, brevistylous flower, top view; C, flower, lateral view; D-F, S. coccinea H. S. Lo: D, flower, lateral view; E, longistylous flowers, top view; F, habit

FIG. 3. — Holotype of Spiradiclis coccinea H. S. Lo, S. H. Chun 13475 (IBSC 0510628).