Impatiens tenerrima Y. L. Chen

Plants annual, 5-10 cm tall, soft. Stem very slender, succulent, opposite-branched at middle part, rarely simple, often with 1 pair of suborbicular leaves at middle. Leaves alternate, petiolate; leaf blade ovate or broadly ovate, 1-3 × (0.8-)1-1.7 cm, thinly membranous, without glands, lateral veins 3 or 4 pairs, base broadly cuneate or truncate, glands absent, margin remotely coarsely crenate, apex shortly acute, mucronulate. Inflorescences axillary, 1-flowered; peduncles ca. as long as petioles or longer, often pendulous. Pedicels bracteate below flowers; bracts persistent, ovate, ca. 2 × 1 mm, submembranous, 1-veined, apex acuminate. Flowers yellow, with a brown-purple lower sepal, smaller, ca. 8 mm deep. Lateral sepals oblong or ovate-oblong, 5-6 × ca. 2.5 mm, thinly membranous, apex cuspidate, abaxial midvein slightly turgid-carinate. Lower sepal purple-brown striate, navicular, 4-5 mm deep, without a spur. Upper petal white, suborbicular, ca. 8 mm in diam., base slightly cordate, apex rostellate, abaxial midvein narrowly carinate; lateral united petals ± clawed, 2.5-3 cm, 2-lobed; basal lobes ovate-lanceolate, apex acuminate; distal lobes oblong-lanceolate, ca. 3 × as long as basal lobes, broader, apex elongate into a linear thread 1.7-1.8 cm; auricle inflexed, obliquely triangular. Filaments linear, 4-6 mm; anthers obtuse. Ovary fusiform, ca. 4 mm. Capsule not seen. Fl. Aug.

SW Sichuan (Muli).

● Forest understories, stony places; ca. 2800 m.