2. Mitragyna hirsuta Haviland, J. Linn. Soc., Bot. 33: 72. 1897.
毛帽蕊木 mao mao rui mu
Paradina hirsuta (Haviland) Pitard.
Trees, deciduous, to 20 m tall; branches angled to terete, densely pilosulous to glabrescent. Petiole 5-30 mm, glabrous to densely pilosulous; leaf blade drying stiffly papery, suborbicular to broadly elliptic or ovate, 8-18(-30) × 2-12(-20) cm, adaxially glabrous, abaxially sparsely to densely pilosulous or rarely glabrescent, base broadly obtuse to cordulate, apex rounded to acute; secondary veins 6-12 pairs, spreading, sometimes with pilosulous domatia in abaxial axils; stipules elliptic-oblong to ovate, 10-20 × 8-15 mm, pilosulous and weakly keeled, apex obtuse to rounded. Inflorescences densely puberulent to pilosulous; flowering heads sessile, 7 to numerous, 10-12 mm in diam. across calyces, 20-25 mm in diam. across corollas; bracteoles linear-spatulate, 2.5-3.5 mm, glabrous to sparsely pubescent and/or ciliolate. Calyx glabrous; ovary portion obconic, 1.2-2 mm; limb deeply lobed; lobes oblanceolate to spatulate, 1.5-2.5 mm, entire to ciliolate. Corolla yellow, outside glabrous, inside densely hairy; tube 5-6 mm; lobes narrowly elliptic, 2-2.5 mm, acute. Fruiting heads 15-20 mm in diam. Capsules 5-8 mm, weakly ridged; seeds ca. 1 mm. Fl. [Jun-Jul, Dec], fr. [Apr, Dec].
Forests; [100-1500 m]. Yunnan [Cambodia, Laos, Myanmar, Thailand, Vietnam].
This species was illustrated by Ridsdale (Blumea 24: 60, f. 6. 1978).