13. Ophiorrhiza densa H. S. Lo, Bull. Bot. Res., Harbin. 10(2): 57. 1990.
密脉蛇根草 mi mai she gen cao
Herbs or subshrubs, ascending, to 1 m tall; stems terete, drying brownish purple, brown pilosulous to glabrescent. Leaves in subequal pairs; petiole 1-3 cm or longer, densely pilosulous or tomentose; blade drying thinly papery, adaxially black, abaxially pale purple, ovate or lanceolate-ovate, usually inequilateral, (5-)8-15(-18) × 1.5-4 cm, sparsely pilosulous adaxially, crisped tomentose along veins abaxially, base subcuneate, margins entire, apex caudate; secondary veins 13-18(-23) pairs; stipules caducous, not seen. Inflorescence 4-8 cm, many flowered, brown tomentose; axes helicoid; bracteoles linear, ca. 3 mm. Flowers distylous, sessile to subsessile. Calyx hispidulous; hypanthium turbinate to subglobose, ca. 1.2 mm, 5-ribbed; lobes narrowly triangular, ca. 1 mm. Corolla pale purple, subtubular to inflated, densely pilosulous outside, inside pilosulous near middle of tube and sometimes onto lobes, and/or densely glandular-pilose on lobes; tube ca. 10 mm; lobes subdeltoid, ca. 1.5 mm, dorsally with very short horn, apex rostrate. Capsules unknown. Fl. Nov.
● Dense forests; 1400-1600 m. Yunnan (Malipo).
In the protologue and FRPS (71(1): 158. 1999), H. S. Lo described the floral forms as having similar corollas and reciprocally placed anthers and stigmas near the middle of the corolla tube and shortly exserted, respectively. However, the protologue figure showed differences between the floral forms in the internal pubescence of the corollas, with the pubescence confined to the general area of the middle of the tube in the short-styled flowers but distributed from the middle of the tube to the tops of the lobes in the long-styled form; this internal corolla pubescence was not described in the protologue text. The insides of the corolla lobes were described as "glanduloso-piloso" in the protologue text, which is unusual and also not shown in one of the protologue figures of the corolla interior.