Description from Flora of China
Mazus pulchellus var. primuliformis Bonati.
Perennials, ca. 20 cm tall, densely white or rusty pubescent, glabrescent. Roots fibrous, tufted. Rhizomes short. Leaves all basal, rosulate; leaf blade obovate-spatulate to oblong-spatulate, to 20 cm, papery, base tapering, margin incised-serrate, double serrate, or irregularly pinnately parted, apex rounded. Scapes 1-5, herbaceous, erect or ascending, simple or sparsely branched. Racemes lax, numerous flowered; bracts narrowly lanceolate, 2-5 mm. Pedicel slender, to 4 cm. Calyx campanulate, 5-7 mm; lobes much shorter than tube, narrowly ovate, apex acute, veins inconspicuous. Corolla red, purple, or dark violet, 2-2.5 cm; lower lip lobes sparsely fimbriate-toothed, middle lobe narrower and longer than lateral lobes; upper lip erect, short, lobes subrounded, margin fimbriate-toothed, apex truncate. Ovary glabrous. Capsule ovoid. Fl. and fr. Mar-Jun.
* Moist places in rocky crevices, forests; ca. 1600 m. W Hubei, SE Sichuan, SE Yunnan.