变红蛇根草 bian hong she gen cao

Herbs, weak to suberect, to 60 cm tall; stems glabrous to pubescent. Leaves in subequal pairs; petiole 0.5-2(-4) cm, densely pilose; blade drying thinly papery, red on both surfaces or grayish green adaxially, lanceolate to ovate, 3-11 × 1-4 cm, glabrous or sparsely strigose adaxially, ?pilose along principal veins abaxially, base cuneate, margins entire or undulate, apex rounded-obtuse to acuminate or acute; secondary veins 7-13 pairs; stipules sometimes caducous, broadly triangular then strongly narrowed, 2-3 mm. Inflorescence congested-cymose, many flowered, densely pubescent; peduncle 1-6 cm; axes helicoid, up to 1 cm, elongating as fruit develop; bracts absent, minute, or caducous. Flowers reportedly distylous, subsessile. Calyx densely pubescent; hypanthium subobcordate, ca. 1 mm, 5-ribbed; lobes subtriangular, ca. 0.5 mm. Corolla slenderly tubular, 6-8(-12) mm, outside pubescent and 5-ribbed at least in bud, inside with white villous ring at middle and scaly pubescent in throat and onto lobes; lobes triangular to subovate, dorsally narrowly winged and with very short horn. Capsules drying purplish red, obcordate, ca. 3 × 7-8 mm, pubescent. Fl. Apr-Jul.

Shady and wet places in forests. Guangxi, Hainan, Yunnan [N Vietnam].

The circumscription of this species here follows that of H. S. Lo in FRPS (71(1): 139. 1999), which partly differs from that of other authors and also conflicts with the protologue in some details. The protologue described the plants as glabrous with filiform stipules and bracts that fall before the fruit mature, while H. S. Lo said they are pubescent with narrowly triangular stipules and lacking bracts. Lo described the flowers as distylous with the corollas apparently similar in both floral forms but unusual in anther position: the forms were described as differing in style length, ca. 2 mm vs. ca. 6 mm, and anther size, ca. 2 mm vs. ca. 3 mm, but with the anthers in both forms positioned near the base of the corolla, at ± the same height as the short-styled stigmas but well below the long-styled stigmas. However, the figure in FRPS (p. 140, t. 33, f. 1-8) differs from Lo’s description in its depiction of well-developed bracts that persist with the flowers, deeply bilobed stipules, corollas with only 1 ring of internal pubescence, glabrous fruit, and flower forms with the anthers of the short-styled flowers exserted on well-developed filaments.