Allocheilos maguanensis W.H. Chen & Y.M. Shui, 2020

Chen, Wen-Hong, Guo, Shi-Wei, Wu, Jian-Yong, Chen, Li & Shui, Yu-Min, 2020, Two new species of Allocheilos (Gesneriaceae) from the karst regions in Yunnan, China, PhytoKeys 157, pp. 155-166 : 155

Allocheilos maguanensis W.H. Chen & Y.M. Shui sp. nov. Figs 2 , 3

Diagnosis.

The new species is similar to A. cortusiflorus W.T.Wang in glandular-villous corolla on the adaxial surface and style longer than ovary, but differs in its broadly ovate bracts (vs. linear), calyx lobes elliptic (vs. linear), 11.1-11.3 mm long corolla (vs. 8.5-9.5 mm), inner two lobes bigger than outer two lobes (vs. equal between them), staminoides major 3-4 mm long (vs. minor 0.4-0.5 mm), and 1.0-1.1 cm longer mature fruit (vs. 1.5-1.8 cm).

Type.

China. Yunnan province, Maguan county, Bazhai town, 23°06'34"N, 104°03'18"E, on the cliffs of a limestone mountain, elev. ca. 1750 m, introduced on 7 April 2017 from the above locality to Kunming Botanic Garden (KBG), in flower on 11 July 2017 in KBG and prepared for specimens there, Y.M. Shui, S.W. Guo et al. B2017-1343 (holotype, KUN).

Herbs perennial. Rhizome short, stem absent. Leaves basal, opposite; petiole 7-13 cm long, brown-red villous; blade herbaceous, slightly asymmetric, ovate to rounded, 7.5-10 × 7-9.5 cm, base cordate, apex obtuse, margin crenate, adaxially densely depressed white pubescent, abaxially white pubescent and brown-red villous along the nerves; venation palmate, lateral veins 5-7 on each side of midrib. Inflorescences axillary, cymes with many flowers; peduncle 11-12.5 cm, densely glandular brown-red villous; bracts 2, broadly ovate to rounded, 0.8-1 × 0.7-0.8 cm, adaxially strigose, abaxially densely villous, margin crenate, apex acute; bracteoles 2, broadly ovate, ca. 6 × 3 mm, adaxially strigose, abaxially densely villous; pedicel ca. 1-1.5 cm, glandular-villous. Calyx 5-parted to the base; segments elliptic, 4 × 1-2 mm, apex beaked, margin entire, adaxially sparsely glandular brown-red villous, abaxially densely pubescent. Corolla white, campanulate, zygomorphic, 1-1.3 cm long, ca. 0.4 cm wide at the throat, outside glandular-villous, inside glabrous, tube ca. 4 mm long; limb 2-lipped; adaxial lip ca. 9 mm long, 4-lobed to 1/3 of the lip, lobes triangular, ca. 3 mm long; abaxial lip lanceolate, undivided, ca. 9 × 3 mm. Stamens 2, adnate to the corolla ca. 2 mm above base; anthers 2, coherent laterally; filaments ca. 6 mm long, sparsely villous above middle and barbate near the anthers; staminodes 3, glabrous, adnate to the corolla tube ca. 2 mm above base. Disc ring-like, ca. 0.5 mm high. Pistil 1.5-1.8 cm long; ovary oblong, ca. 3 mm long, densely strigose and glandular strigose; style linear, ca. 1.5 cm long, densely strigose and glandular strigose; stigma 1, capitate. Capsule linear, 1.0-1.1 cm long.

Phenology.

Flowering is from June to July (in the greenhouse).

Etymology.

The epithet means the type locality of the new species.

Distribution and ecology.

The new species is only distributed in the type locality, SE Yunnan, SW China. It grows in the limestone evergreen broad-leaved forests near the summit of the limestone hills. The main companying plants are Sinosenecia oldhamianus (Maxim.) B. Nord. in Compositae , Petrocosmea minor Hemsl. and Paraboea rufescens (Franch.) Burtt in Gesneriaceae , Scutellaria sichourensis C.Y.Wu et H.W.Li in Labiatae , Eria coronaria (Lindl.) Rchb. f., and Bulbophyllum andersonii (Hook.f.) J.J.Sm in Orchidaceae .

Provisional conservation status.

Based on observations around the locality, this new species was found in two localities with two minor populations in Maguan Xian, Yunnan province, China. One population grows on limestone cliff around 10 mature individuals, and was easily disturbed by human activities. Another population grows among rocks of the limestone hills with around 20 mature individuals. Thus, further exploration should be conducted while an urgent conservational project is needed for this rare species with extremely small populations ( Ma et al. 2013). So far, the species can be provisionally considered as Critically Endangered, CR: B1ab (iii) + 2ab (iii). ( IUCN 2012; IUCN Standards and Petitions Subcommittee 2017).

Additional examined specimens.

China. Yunnan province, Maguan county, Bazhai town, 7 April 2017 introduced to KBG, S.W. Guo et al. BZL04-012 (KUN). Maguan county, Pojiao town, 23°06'28"N, 104°18'30"E, 13 October 2017 introduced to KBG, Y.M. Shui, W.H. Chen, S.W. Guo, H.H. Xi et al. B2018-495 (KUN). Maguan county, Pojiao town, Y.M. Shui, W.H. Chen, S.W. Guo et al. PJL07-006 (KUN); ibid, 13 October 2017, S.W. Guo, H.H. Xi PJL14-017 (KUN).

Discussion.

The new species has obvious staminodes, which are usually difficult to observe on specimens in herbaria. So after the detailed observation in the field, the diversity of staminodes will provide us with an opportunity to explore its evolutionary implications for the genus in Gesneriaceae .

Figures

Figure 2. Vegetative morphology of Allocheilos maguanensis W. H. Chen & Y. M. Shui, sp. nov. (A, B, D-H from Y. M. Shui, W. H. Chen, S. W. Guo, H. H. Xi et al. B 2018 - 495 C from Y. M. Shui, S. W. Guo et al. B 2017 - 1343) A-C habit and plants D adaxial surface of leaves E abaxial surface of leaves F close-up of petiole G indumenti on the adaxial surface of leaves H indumenti on the abaxial surface of leaves.

Figure 3. Flower morphology of Allocheilos maguanensis W. H. Chen & Y. M. Shui, sp. nov. (A-C, E, F, H from Y. M. Shui, S. W. Guo et al. B 2017 - 1343 D, G, I, J from Y. M. Shui, W. H. Chen, S. W. Guo, H. H. Xi et al. B 2018 - 495) A, B inflorescence showing the wide bracts C face and lateral view of flowers D, E opened corolla showing stamens and staminodes F, G close-up of stamens coherent laterally H calyx showing ovate segments with beaked apex I face view of flower showing the white staminode inside J disk at the base of the ovary. Notes: at anther, br bract, cx calyx lobe, dc disc, fm filament, gl glandular, sd staminode, sm stigma.