2. Andrographis laxiflora (Blume) Lindau in Engler & Prantl, Nat. Pflanzenfam. 4(3b): 323. 1895.
疏花穿心莲 shu hua chuan xin lian
Justicia laxiflora Blume, Bijdr. 789. 1826; Andrographis glomeruliflora Bremekamp; A. laxiflora var. glomeruliflora (Bremekamp) H. Zhu; A. monglunensis Hung T. Chang & H. Zhu; A. tenera (Nees) Kuntze; A. tenuiflora T. Anderson, nom. illeg. superfl.; Haplanthoides yunnanensis H. W. Li; Haplanthus tener Nees.
Herbs to 50 cm tall, isophyllous or anisophyllous. Stems erect or procumbent, 4-angled, glabrous or pubescent. Petiole 3-10 mm; leaf blade ovate, 1.5-9 × 1.5-3(-5.5) cm, both surfaces glabrous, secondary veins 5 or 6 pairs on each side of midvein, base slightly attenuate and decurrent onto petiole, margin entire, apex acuminate to shortly acuminate. Inflorescences axillary or terminal, racemes or panicles of racemes, these sometimes reduced and flowers appearing as clusters in leaf axils or at ends of long peduncles; rachis glabrous or pubescent (trichomes non-gland-tipped or gland-tipped); bracts linear, subulate, or lanceolate, 1-3 mm, glabrous or pubescent; bracteoles subulate, glabrous or pubescent. Pedicel 0.5-2 mm, glabrous or pubescent. Calyx 2-4 mm, outside glabrous or pubescent, lobes subulate. Corolla white with purplish or pinkish coloration on lips, 0.8-1.2 cm, outside pubescent with gland-tipped trichomes; tube 6-9 mm, base curved, dorsally ± gibbous; lower lip 1.5-4 mm, lobes 0.5-2 mm; upper lip 1.5-4 mm, erect (± parallel to lower lip), entire to 2-lobed. Stamens included in corolla tube. Capsule linear-cylindric, 10-20 × ca. 2 mm, glabrous or pubescent with gland-tipped trichomes, 16-20-seeded. Seeds ca. 1 × 0.7 mm, rugose. Fl. Aug-Nov, fr. Nov-Mar.
Thickets, bamboo forests; 200-1500 m. Guangxi, Guizhou, Hainan, Yunnan [Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Thailand, Vietnam].
Specimens misidentified as Gymnostachyum sanguinolentum (Vahl) T. Anderson (C. Y. Wu, Index Fl. Yunnan. 2: 1676. 1984; C. C. Hu, FRPS 70: 75. 2002) belong here.
Variation is evident in the pubescence of rachises, pedicels, bracts, bracteoles, and calyces among plants of Andrographis laxiflora. These structures may be glabrous, have non-glandular trichomes only, have gland-tipped trichomes only, or have a mixture of gland-tipped and non-glandular trichomes. Capsule may be glabrous or pubescent with gland-tipped trichomes only. Plants with gland-tipped trichomes on the calyces and capsules have been treated as A. laxiflora var. glomeruliflora (C. C. Hu, FRPS 70: 205. 2002). Because varying degrees of pubescence are evident on calyces and capsules among specimens from within and outside of China, and because these same differences are not taxonomically recognized for plants of A. paniculata that show the very same variations, var. glomeruliflora is not recognized here (in keeping with B. Hansen, Nordic J. Bot. 5: 353-356. 1985, who did not recognize it as distinct).