Description from Flora of China
Rubia ustulata Diels.
Herbs, perennial, with rootstock and somewhat thickened storage roots; stems usually clumped, suberect, to 0.5 m, quadrangular or narrowly 4-winged, hirsute at nodes to glabrescent, smooth or rarely scabrid. Leaves in whorls of 4(-6), subsessile; blade drying papery, lanceolate, ovate, obovate, elliptic-oblong, broadly elliptic, or suborbicular, 1-4(-5) × 0.3-2 cm, both surfaces hairy to scabrid, base cuneate to rounded, margins flat or often revolute, apex acuminate, shortly cuspidate, or acute; principal veins 3(or 5), palmate. Inflorescences thyrsoid, paniculate, terminal and axillary cymes usually longer than subtending leaves; axes subglabrous to sparsely hirsutulous; bracteoles lanceolate, 2-5 mm; pedicels 1-3 mm. Ovary 0.3-0.4 mm in diam., glabrous. Corolla yellow or pale yellow, rotate, ca. 3 mm in diam., glabrous; fused basal part ca. 0.5 mm; lobes subovate, 1.2-1.5(-2) mm, apex thickened, incurved, shortly rostrate. Mericarp berries not seen.
In his publication of Rubia yunnanensis Diels referred to an unpublished herbarium name "R. sikkimensis var. yunnanensis Franchet" and commented that "it is quite different from R. sikkimensis." Rubia ustulata was published on the same page immediately after R. yunnanensis and said to differ by its smaller size, smaller and more equal leaves and leaflike stipules, and more cuspidate petals. In view of the variability of these characters, its synonymization by H. S. Lo (in FRPS 71(2): 303. 1999) is accepted. The species evidently has a considerable altitudinal range and consequently varies from quite elongated to considerably condensed. Within R. sect. Oligoneura, R. yunnanensis belongs to the R. mandersii group of SW China.
● Thickets, grassy slopes, roadsides; 1700-3000 m. Sichuan, Yunnan.