Paraisometrum mileense W. T. Wang

Petiole 0.2-4.2 cm, brownish woolly; leaf blade elliptic to oblong elliptic, 2-4.8 X 1.2-1.8 cm, adaxially densely appressed white pubescent, abaxially densely brownish woolly, margin obtusely denticulate, apex obtuse to rounded. Peduncle 6.5-12 cm, densely brownish pubescent; bracts lanceolate-linear, 7-10 1.2-3 mm. Calyx segments lanceolate-linear, 3-5.3 X 0.8-1 mm, outside densely tomentose. Corolla 1.6-1.8 cm; tube 1.3-1.4 cm; adaxial lip 3-4 X ca. 8.5 mm, lobes triangular, central 2 ca. 1.2 mm, lateral 2 ca. 1.6 X 2 mm; abaxial lip deltoid, ca. 2.2 X 3 mm. Stamens ca. 6 mm, glabrous; staminode ca. 0.8 mm. Pistil ca. 1 cm, glabrous; ovary ca. 9 mm. Fruit unknown. Fl. Feb.

SE Yunnan (Mile Xian).

Flowering in August; fruiting in October.

Paraisometrum appears most closely related to Isometrum. Both genera share the presence of 4 fertile stamens, the corolla limb much shorter than the corolla tube, and the 5 corolla lobes nearly equal in length. The genus Isometrum is restricted to southwestern and central China. Paraisometrum differs from Isometrum in its corolla with a 4-lobed upper lip and an undivided lower lip, stamens that are adnate to above the middle of the corolla tube, and the pistil with one stigma (Weitzman et al., 1997).

The genus Paraisometrum only includes one species Paraisometrum mileens, which is occurring in Shilin County, Mile County of SE Yunnan, China.

Herbs perennial, stemless, short rhizomatous. Leaves basal, 7-10; petiole 0.2-4.2 cm, brownish lanate; leaf blade elliptic to oblong-elliptic, 2-4.8 cm long, 1.2-1.8 cm wide, leathery, adaxially densely appressed white pubescent, abaxially densely brownish lanate; base cuneate to broadly cuneate, margin obtusely denticulate, apex obtuse to rounded; lateral veins 5 or 6 pairs, adaxially impressed, abaxially slightly prominent. Cyme 1-3, branched 1 or 2, 3-8-flowered; peduncle 6.5-12 cm, densely brownish pubescent; bracts lanceolate-linear, 7-10 mm long, 1.2-3 mm wide, outside densely brownish lanate, inside glabrous. Pedicel 0.6-2.2 cm, puberulous and glandular-puberulous. Calyx segments lanceolate-linear, 3-5.2 × 0.8-1 mm, outside densely puberulous, inside glabrous, apex acute. Corolla purple, 1.6-1.8 cm, outside glandular-puberulous, inner surface of lobes densely minutely puberulous; tube funnelform-tubular, 1.3-1.4 cm, mouth 3.5-5 mm diameter; upper lip 3-4 × ca. 8.5 mm, 4-lobed, lobes triangular, central 2 smaller, ca. 1.2 × 1 mm, lateral 2 larger, ca. 1.6 × 2 mm; lower lip undivided, deltoid, ca. 2.2 × 3 mm. Stamens adnate for 9-10 mm above corolla base, glabrous; filaments narrowly linear, ca. 5 mm; anthers coherent in pairs, ellipsoid, ca. 0.8 mm; staminode adnate for ca. 2.2 mm above corolla base, filiform, ca. 0.8 mm, glabrous. Pistil ca. 10 mm, glabrous; ovary linear, ca. 9 × 1 mm; style ca. 1 mm; stigma depressed-capitate.

Growing in limestone under forest; 2000-2600 m.

Paraisometrum mileense là một loài thực vật có hoa trong họ Tai voi. Loài này được W.T. Wang mô tả khoa học đầu tiên năm 1997.