Stachys yingzuijieensis L.Wu & Y.P.Chen, 2023

Xue, Ling, Cai, Jia-Hua, Zhan, Min, Li, Xiao-Ping, Wu, Lei & Chen, Ya-Ping, 2023, Molecular and morphological evidence for a new species of Stachys (Lamiaceae) from Hunan, China, PhytoKeys 236, pp. 121-134 : 121

Stachys yingzuijieensis L.Wu & Y.P.Chen sp. nov.

Figs 3 , 4

Type.

China, Hunan, Huitong County, Yingzuijie National Nature Reserve , alt. 300-800 m, 26°56′N, 109°54′E, 3 Aug 2022, L. Wu et al. YZJ0145 (holotype: CSFI079941!; isotype: CSFI!) .

Diagnosis.

Stachys yingzuijieensis is most closely related to S. arrecta , but differs in its lamina oblong to elliptic-lanceolate (vs. cordate) with margin crenulate (vs. coarsely serrate), corolla white (vs. pink with purple spots) with tube included in calyx (vs. exerted from calyx) and nutlet surface smooth (vs. verrucate).

Herbs perennial. Rhizomes white, densely glandular pubescent. Stems erect, simple, 50-75 cm long, quadrangular, densely villous and glandular pubescent. Leaves opposite; petioles 2-4 cm long, densely villous and glandular pubescent; lamina oblong to oblong-lanceolate, papery, 10-16 × 4-6 cm, apex acute, margin crenulate, base cordate, adaxially green, sparsely villous and glandular pubescent, abaxially light green, densely villous and glandular pubescent, lateral veins 4-5-paired, conspicuously elevated abaxially. Verticillasters 6-flowered, flowers sessile; bracts leaf-like, upper ones sessile, lanceolate, densely villous and glandular pubescent on both surfaces, longer than verticillasters; bracteoles linear, 1-2 mm long. Calyx campanulate, ca. 7 mm long, 10-veined, densely villous and glandular pubescent outside, glandular pubescent inside, fruiting calyx dilated, ca. 9 mm long; teeth 5, subequal, ovate-lanceolate, ca. 3 mm long, apex spinescent. Corolla white, ca. 1 cm long, tube ca. 7 mm long, ca. 1.5 mm wide, pubescent annulate inside at 1/3 distance from base; 2-lipped, upper lip erect, concave, subcircular, ca. 3 mm in diam., densely pubescent and glandular pubescent outside, glabrous inside, lower lip spreading, sparsely pubescent and glandular pubescent to glabrescent outside, glabrous inside, ca. 6 mm long, 3-lobed, medium lob largest, trapeziform, ca. 3 mm long, ca. 4 mm wide, apex entire or emarginate, lateral lobs oblong, ca. 2 mm long, ca. 1 mm wide. Stamens 4, straight, included, filaments pubescent and glandular pubescent, anther cells 2, divergent. Style included, glabrous, apex subequally 2-lobed, lobes subulate. Ovary rounded at apex, glabrous. Nutlets 4, dark brown, ovoid, ca. 1.5 mm in diam., smooth and glabrous.

Phenology.

Flowering from July to September, fruiting from August to October.

Distribution and habitat.

Currently, S. yingzuijieensis is only known from the Yingzhuijie National Nature Reserve and a total of 50 mature plants were found during our field investigation. The new species usually grows in shady and moist places in evergreen broad-leaved forests at an altitude of 300-800 m.

Etymology.

The specific epithet is derived from the type locality of the new species, i.e. the Yingzuijie National Nature Reserve in western Hunan Province, China.

Chinese name (assigned here).

yīng zhuǐ jiè shuǐ sū (鹰嘴界水苏).

Additional specimen examined.

China. Hunan: Huitong County, Yingzuijie National Nature Reserve, 8 Aug 2022, L. Wu et al. YZJ0654 (CSFI!).

Figures

Figure 3. Morphology of Stachys yingzuijieensis from the type locality A habitat B habit C-D inflorescence E adaxial view of lamina F abaxial view of lamina G roots and rhizomes H frontal view of corolla I lateral view of calyces J dissected corolla K nutlets (A-J photographed by Lei Wu K photographed by Ya-Ping Chen).

Figure 4. Holotype specimen of Stachys yingzuijieensis.