Microtoena wawushanensis Xue X. Wu & Qiang Wang, 2024

Wu, Xue-Xue, Wang, Yan, Chen, Yan-Yi & Wang, Qiang, 2024, Microtoena wawushanensis (Lamiaceae, Lamioideae): A new species from Sichuan, China, PhytoKeys 250, pp. 223-236 : 223-236

Microtoena wawushanensis Xue X. Wu & Qiang Wang sp. nov.

Figs 3 , 5 , 6

Type.

China • Sichuan Province Meishan City, Hongya County, Wawushan Nature Reserve , growing under the forest by the edge of a riverside, 29°32.2832'N, 102°55.6359'E, 1500 m alt., 14 September 2023, X. X. Wu et al. WXX 23001 (holotype: PE 02462560 ; isotypes: PE 02462561 , PE 02462562 , PE 02462563 , PE 02462564 , PE 02462565 ) .

Diagnosis.

Microtoena wawushanensis is morphologically similar to M. moupinensis (Franch.) Prain and M. prainiana Diels (Table 2 ), but differs from M. moupinensis and M. prainiana by having a crenate leaf margin with distinct mucrones (vs. with or dentate without any mucro), a cuneate to truncate-subcordate leaf base (vs. truncate-subcordate or cuneate leaf base), a lax, more or less compact to spike-like panicle inflorescence (vs. inflorescence sometimes with one-sided branches or shortly ovoid panicles), linear to lanceolate bracts (vs. linear or ovate bracts), calyx teeth that are triangular-lanceolate, linear-lanceolate to subulate with an apex usually hooked (vs. similar or calyx teeth subulate with a conspicuously hooked apex), a highly variable and unstable calyx tooth ratio: 1.36–2.13 (vs. 1.03–1.49 or five subequal calyx teeth), a white corolla marked with red on both upper lip and the lateral lobes of the lower corolla (vs. yellow or pale yellow corolla) and filaments are barbate at both the upper and basal parts, with the hairs in the middle section being almost imperceptible (vs. filaments are clearly barbate from the lower to middle part).

Description.

Herbs perennial. Stems erect, 0.40–0.80 m tall, base sometimes woody, sparsely puberulent. Leaf petiole 3–9 cm long; leaf blade ovate to oblong-ovate, triangular-ovate, 3.91–9.86 cm long, 3.91–9.86 cm broad, sparse hairs on the adaxial surface, with few hairs visible only along the veins on the abaxial surface and the rest of the abaxial surface glabrous; base truncate or cuneate; margin coarsely serrate to mucronate crenate, with distinct mucrones; apex acuminate to shortly caudate-acuminate. Cymes axillary and terminal, dichotomous, lax, slightly to very compact in spike-like panicles; peduncle inconspicuous. Bracts usually linear to lanceolate, 2.10–11.40 mm long, 0.40–0.80 mm broad. Calyx is 0.38–0.80 cm long at anthesis, densely puberulent, dilated after anthesis and 5 - toothed; calyx teeth are triangular-lanceolate, linear-lanceolate to subulate, with the tooth ratio highly variable and unstable and the apex is usually hooked. Corolla white, marked with red on upper lip, 1.76–3.59 cm long, hirsutulous outside; corolla tube conspicuous; upper corolla lip laterally compressed; lower corolla lip 3 - lobed, middle lobe subcircular, wider than lateral lobes, lateral lobes marked with red. Stamens 4, filament barbate at the upper and basal parts, while the middle section has nearly imperceptible hairs. Nutlets dark brown to black, smooth.

Distribution and habitat.

Currently, M. wawushanensis has been found in Wawushan Nature Reserve, Hongya County, Meishan City, Sichuan Province, China. It occurs by the edge of a riverside with weak light, at an elevation of 1500 m. In the type locality, the companion species mainly include Bistorta amplexicaulis (D. Don) Greene , Urtica fissa E. Pritz. , Lecanthus peduncularis (Wall. ex Royle) Wedd. , Cyathula officinalis K. C. Kuan , Sinacalia davidii (Franch.) Koyama and Stachyurus chinensis Franch.

Phenology.

Flowering from August to September, fruiting in September.

Etymology.

The specific epithet is derived from the type locality of the new species, i. e. the Wawushan Nature Reserve in southwest Sichuan Province, China and the Latin suffix- ensis, indicating the place of origin or growth.

Vernacular name.

(assigned here). Simplified Chinese: 瓦屋山冠唇花 (Chinese pinyin: wǎ wū shān guàn chún huā).

Conservation assessment.

The ongoing field investigation has identified only one population of this taxon that is endemic to the Wawushan Nature Reserve. Additional fieldwork is necessary to gain a better understanding of this species. According to the guidelines of the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022), Microtoena wawushanensis is assessed as data deficient ( DD).

Figures

Figure 3. Images of Microtoena wawushanensis sp. nov. A individual in the flowering period of wild populations B, C inflorescence in lateral view D lower corolla lip E dissected calyxes (outside & inside) F calyxes G bracts H leaves I dissected corolla (containing filaments) and corola.

Figure 5. Line drawing of Microtoena wawushanensis sp. nov. A the whole plant B flower (frontal view) C dissected corolla D calyx with two bracts E bract. (Drawn by Ai-Li L).

Figure 6. Holotype of Microtoena wawushanensis sp. nov. (PE 02462560).