Hemiboea suiyangensis Z.Y.Li, S.W.Li & X.G.Xiang, 2018

Li, Shuwan, Han, Mengqi, Li, Xiaojie, Li, Zhenyu & Xiang, Xiaoguo, 2018, Hemiboea suiyangensis (Gesneriaceae): a new species from Guizhou, China, PhytoKeys 99, pp. 99-106 : 99

Hemiboea suiyangensis Z.Y.Li, S.W.Li & X.G.Xiang sp. nov. Figs 1 , 2

Diagnosis.

Hemiboea suiyangensis is easily distinguished from other Hemiboea species by having an oblique-infundibular corolla with abaxial gibbous, swollen on the upper half of the tube, throat and lower lobes densely villose. The species is similar to H. omeiensis W.T.Wang (1982: 127) in the shape of the leaf blade, but can be distinguished by oblate involucre (vs. globose), unequal calyx segments (vs. equal) and corolla with densely villose throat and lower lobes, lemon-yellow outside (vs. corolla with glabrous throat and lower lobes, white outside) (Fig. 3 , Table 1 ).

Type.

China. Guizhou province: Suiyang County, Xiangshuwan , growing in cave entrance of limestone hills, about 885 m, 10 Aug. 2015, M. Q. Han and S. W. Li HMQ 881 (holotype: IBK!, isotypes: IBK!, PE!) .

Perennial herbs.

Stems ascending, subterete, 20-45 cm tall, 3-5 mm in diam., simple, sparsely purple-spotted, glabrous, slightly juicy when fresh, nodes 4-7, not swollen. Leaves opposite, unequal to sub-equal in a pair, herbaceous; leave blade oblong-lanceolate, ovate-lanceolate or elliptic, 4.5-19 cm long, 2.2-8 cm wide, apex acuminate, rarely acute, margin repand-crenate, base usually oblique, one side narrowly cuneate to cuneate, the other side cuneate to rounded, adaxial surface green, sparsely pubescent, abaxial surface pale green to purple, glabrous; lateral veins 6-13 on each side of midrib, vermiform sclereids surrounding the vascular bundles, veinlets inconspicuous; petiole 1-8.5 cm long, about 2 mm in diam., almost terete, adaxially valleculate, margins erect and rounded, glabrous, purple or purple maculate. Cymes pseudoterminal, sometimes axillary, 3-9(-12)-flowered; peduncle 1-2 cm long, about 2 mm in diam., glabrous, purple-spotted; involucre oblate, apiculate, 2.3-3.3 cm in diam., pale green, glabrous; pedicle 3-5 mm long, about 2 mm in diam., glabrous. Calyx white, glabrous, 5-parted to base; segments linear or linear-lanceolate, 11-13 mm long, 2-3 mm wide, unequal, adaxial three longer, ca. 13 mm long, abaxial two shorter, ca. 10 mm long. Corolla oblique-infundibular, 3.2-4 cm long, outside lemon-yellow, densely glandular-pubescent, inside glabrous, purple-spotted at throat, densely glandular-pubescent inside adaxial gibbous side of the tube, densely villose at the throat and lower lobes, a pilose ring 4-6 mm above corolla base; tube 2.5-3 cm long, 2.5-4 mm in diam. above base, swollen on abaxial side of the upper half of tube, 12-14 mm in diam. at mouth, gibbous; limb two-lipped, adaxial lip 3-3.5 mm long, 2-lobed at apex, lobes equal, nearly semi-orbicular, abaxial lip 7-10 mm long, 3-parted, lobes subequal, oblong, expanded to reflexed after anthesis. Protandrous; stamens 2, abaxial, adnate to 16-17 mm above corolla base, included, glabrous; filaments narrowly linear, 11-13 mm long, about 1 mm wide; anthers ovate-elliptic, 3-3.8 mm long, about 2 mm wide, coherent at apex; staminodes 3, adaxial, adnate to 8-11 mm above corolla base, glabrous, unequal, lateral two narrowly linear, 9-11 mm long, about 1 mm wide, apex capitellate, separate, central one linear, 2-3 mm long, about 1 mm wide, apex truncate. Disc ring-like, lemon-yellow, 1.4-1.7 mm high, margin repand. Pistil 18.7-19 mm long; ovary linear, 8.7-9 mm long, glabrous, about 3 mm wide; style ca. 10 mm long, about 1 mm in diam., sparsely glandular-puberulent; stigma oblate.

Distribution.

Only known from the Xiangshuwan, Suiyang County, Guizhou province, China.

Phenology.

The new species was observed flowering from June to August.

Habitat and ecology.

Hemiboea suiyangensis grows on moist stone at the limestone cave entrances, next to the stream. The main companion species are: Pilea notata C. H. Wright, Elatostema prunifolium W.T. Wang, Acorus gramineus Solander ex Aiton, Ficus tikoua Bureau and Impatiens chlorosepala Hand.-Mazz.

Etymology.

The species is named after the type locality, Suiyang County, Guizhou, China.

Key to Hemiboea suiyangensis and its alliance

1	Petioles flattened adaxially, usually winged and connate perfoliate, especially upper pairs; vermiform sclereids dispersed in leaf mesophyll	H. subcapitata Clarke
-	Petioles subterete, wingless, free; vermiform sclereids surrounding vascular bundles of leaf.	2
2	Corolla lemon-yellow outside, oblique-infundibular, with densely villose throat and lower lobes; disc lemon-yellow, 1.4-1.7 mm high	H. suiyangensis Z.Y.Li, S.W.Li & X.G.Xiang
-	Corolla white outside, tubular-infundibular, with glabrous throat and lower lobes; disc white, 1-1.2 mm high.	3
3	Leaf blade with 8-10 lateral veins each side; cymes 3-6-flowered; corolla tube with dark-purple spots inside; staminodes 3	H. omeiensis W.T.Wang
-	Leaf blade with 4-6 lateral veins each side; cymes 1-3-flowered; corolla tube with pink purple spots inside; staminodes 2	H. gracilis Franch.

Proposed IUCN Conservation Status

According to field observations, Hemiboea suiyangensis has one known population of less than 20 mature individuals. The species is endemic in karst areas and is attributed to the diversity of cave plants. The population and habitat are susceptible to human activities, e.g. collection or deforestation. The species is considered to be "Critically Endangered" (CR) according to the IUCN Red List criteria ( IUCN 2012), based on Criterion D, Population size estimated to number fewer than 50 mature individuals.

Figures

Figure 1. Hemiboea suiyangensis. A Plant B, C Flower outside view D Calyx segments E Flower inside view F Pistil.

Figure 2. Hemiboea suiyangensis. A habits B flowering branch C flower face view D corolla side view E calyx F corolla inside view G pistillum H anthers I staminodia.

Figure 3. Comparisons between Hemiboea suiyangensis and H. omeiensis, A-B Hemiboea suiyangensis. Photographed by Meng-Qi Han C-D H. omeiensis. Photographed by Xiao-Jie Li.