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Hemiboea albiflora, a new species of Gesneriaceae from Guizhou, China
expand article infoZhaowen Wu§, Zhiyou Guo|, Chaoyi Deng, Zhenyu Li§, Xiaoguo Xiang§
‡ Nanchang University, Nanchang, China
§ Institute of Botany, Chinese Academy of Sciences, Beijing, China
| Qiannan Normal College for Nationalities, Duyun, China
¶ Karst Area Development Institute of Qianxinan, Xingyi, China
Open Access

Abstract

Hemiboea albiflora X.G.Xiang, Z.Y.Guo & Z.W.Wu, sp. nov., a new species of Gesneriaceae from Guizhou, China, is described and illustrated. This species was previously listed informally as a variety of H. gamosepala, but it differs significantly from H. gamosepala by its 5-parted calyx from the base, longer peduncle, white corolla and longer pistil. Based on recent extensive observations, this new species is similar to H. cavaleriei var. paucinervis and H. subcapitata but differs from them by its longer petiole, larger involucre, white corolla and longer staminal filaments. The conservation status of this species is considered to be “Vulnerable” (VU) according to the IUCN Red List Categories and Criteria.

Keywords

Hemiboea, Gesneriaceae, limestone flora, new species

Introduction

Hemiboea C.B. Clarke is a medium-sized genus of Gesneriaceae distributed in central to southern China, northern Vietnam and Southern Japan (Li and Wang 2004). Recently, nine new species and one new variety were found in Guangxi, Guizhou and Yunnan province of China (Li and Liu 2004; Wei 2010; Xu et al. 2010, 2012; Huang et al. 2011; Wen et al. 2011, 2013; Pan et al. 2012; Zhou et al. 2013; Zhang et al. 2014; Li et al. 2018; Chen et al. 2018). Meanwhile, Weber et al. (2011) transferred two species of the Chinese endemic genus Metabriggsia W. T. Wang (1983) to Hemiboea, based on molecular and morphological evidence. In addition, Huang et al. (2017) treated H. subcapitata var. pterocaulis Z.Y. Li as a distinct species H. pterocaulis, based on molecular and morphological evidence. In total, the genus Hemiboea comprises at least 36 species and 5 varieties.

During our expedition to Xingyi City, Guizhou Province, China in 2017, we collected two populations of Hemiboea gamosepala var. albiflora C. Y. Deng & M. T. An, nom. nud. invalidly published in Deng and An (2006) (Fig. 1). However, we found that this variety differs significantly from Hemiboea gamosepala Z. Y. Li, especially by the calyx of the variety which is 5-parted from the base. After consulting Hemiboea specimens deposited in PE, KUN, IBK and QNUN and relevant literature (Li 1987; Wang 1983; Li and Wang 2004; Wei 2010), we concluded that it is a distinct species and hence we describe it as Hemiboea albiflora.

Figure 1. 

Distribution of Hemiboea albiflora in China.

Material and methods

Morphological observations and measurements of the new species were carried out, based on living plants and dry specimens (PE, QNUN and XIN). The photographs were taken in the field. All morphological characters were studied under dissecting microscopes and are described using the terminology presented by Wang et al. (1998).

Taxonomic treatment

Hemiboea albiflora X.G.Xiang, Z.Y.Guo & Z.W.Wu, sp. nov.

Figs 2, 3

Type

China. Guizhou: Xingyi City, Maling River Valley, 26°8.47'N, 104°57.27'E, altitude 967 m, on rock faces near the river, 12 October 2017, X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017061 (holotype: PE!; isotypes: PE!, QNUN!).

Diagnosis

H. albiflora differs significantly from H. gamosepala by its 5-parted calyx from the base (vs. 5-lobed from middle), longer peduncle, 3–6 cm (vs. 0.2–0.4 cm), white corolla (vs. pink corolla) and longer pistil, 2–2.5 cm (vs. ~ 1.5 cm). After extensive observations, Hemiboea albiflora is close to H. cavaleriei var. paucinervis W. T. Wang et Z. Y. Li and H. subcapitata C.B. Clarke, but differs from them through its longer petiole, 3–6 cm; larger involucre, 2–3 cm in diameter; white corolla, glabrous outside; and longer staminal filaments, 1.8–2 cm long. The detailed morphological comparisons are listed in Table 1.

Morphological comparisons between H. albiflora and the similar species H. gamosepala, H. cavaleriei var. paucinervis and H. subcapitata.

H. albiflora H. gamosepala H. cavaleriei var. paucinervis H. subcapitata
Leaf
Petiole 3–6 cm 0.6–6 cm 0.5–6.5 cm 0.5–5.5 cm
adaxial surface green, sparsely pubescent deep green, glabrous green, glabrous deep green, glabrous or sparsely pubescent
abaxial surface pale green, glabrous pale green or pale purple, glabrous pale green or purple, glabrous pale green, glabrous or sparsely pubescent
Veins on each side of midrib 5–9 4–10 4–8(-9) 5–6
Flower
Peduncle 2–3 cm long 0.2–0.4 cm long 0.5–6.5 cm long 2–4(-13) cm long
Involucre 2–3 cm in diameter 1.8–2.3 cm in diameter 1–2.5 cm in diameter 1.5–2.2 cm in diameter
Corolla 4–5.5 cm long, outside white, glabrous 3.8–4 cm long; outside pink, sparsely glandular-puberulent 3.0–4.8 cm long, outside white, pale yellow or pink, sparsely glandular-puberulent 3.5–4.2 cm long, outside white, sparsely glandular-puberulent
Tube 3.5–4.5 cm long 3–3.1 cm long 2.3–3.3 cm long 2.8–3.5 cm long
Filaments 1.8–2 cm long 1.2–1.5 cm long 1.0–1.3 cm long 0.8–1.3 cm long
Anther ovate-elliptic, 2–3 mm long subovate, ca. 3 mm long elliptic, 3–3.2 mm long elliptic, 3–4 mm long
Staminodes 2 2 2 3
Pistil 2–2.5 cm long ca. 1.5 cm long 1.7–2.5cm long 3.2–3.5 cm long
Capsule 2–3 cm long 1.8–2.4 cm long 1.5–2.5 cm long 1.5–2.2 cm long

Description

Perennial herbs. Stems ascending, subterete, 40–100 cm tall, 2–5 mm in diameter, simple, sparsely purple-spotted, glabrous, juicy when fresh, nodes 5–10, not swollen. Leaves opposite, herbaceous; petiole 3–6 cm long, about 2 mm in diameter, almost terete, adaxially valleculate, margin erect and rounded, glabrous, green; leave blade oblong-lanceolate or ovate-lanceolate, 7–15 cm long, 3–5.5 cm wide, apex acuminate, rarely acute, margin repand-crenate, base usually oblique, adaxial surface green, sparsely pubescent, abaxial surface pale green, glabrous; lateral veins 5–9 on each side of midrib. Cymes subterminal, sometimes axillary, 4–8-flowered; peduncle 2–3 cm long, 3–4 mm in diameter glabrous, sparsely purple-spotted; involucre subglobose or broad ovoid, 2–3 cm in diameter, yellow-green, glabrous, apex acute. Pedicel 3–5 mm long, 2–3 mm in diameter, glabrous. Calyx white, 5-parted from the base, lobes equal, ovate-lanceolate, 1.2–1.6 cm × 0.3–0.4 cm, glabrous. Corolla white, with mauve lines and spots inside, 4–5.5 cm long, glabrous. Corolla tube 3.5–4.5 cm long, 1–1.4 cm in diameter at the mouth, 4–5 mm in diameter at the base, purple-spotted at throat, densely glandular-pubescent inside adaxial gibbous side of the tube, inside with a ring of hairs adnate to 7–8 mm above the corolla tube base; limb 2-lipped; adaxial lip 0.8–1.0 cm long, 2-lobed at apex, lobes equal, nearly semi-orbicular, abaxial lip 1–1.2 mm long, 3-parted, lobes subequal, oblong. Stamens 2, anthers fused by adaxial surfaces, adnate to 0.8–1 cm above the corolla base; filaments linear, glabrous, geniculate from the middle, 1.8–2 cm long, about 1 mm wide; anthers ovate-elliptic, glabrous, ca. 2–3 mm long, 2 mm wide, coherent at apex. Staminodes 2, glabrous, adnate to 1.2–1.5 cm above the corolla base, thick, 1.2–1.4 cm long, about 1 mm wide, apex capitellate, separate. Pistil 2–2.5 cm long; ovary linear, 0.7–0.9 cm long, 1.5–2.2 mm in diameter, glabrous; style 1.3–1.6 mm long, glabrous; stigma capitate, about 2 mm in diameter. Capsule linear-lanceolate, 2–3 cm long, 2–4 mm in diameter, glabrous, slightly curved.

Figure 2. 

Hemiboea albiflora. A Adaxial leaf blade B flower side view C abaxial leaf blade D flower face view E stem and petioles F opened corolla showing stamens, staminodes and pistil G flowering habit H fruits. Photographs by Zhiyou Guo.

Figure 3. 

Hemiboea albiflora. A Flowering habit B involucre C root D capsule E calyx segments F stamens G staminodes H pistil I flower inside view. Drawn by Zhaowen Wu.

Distribution and habitat

Hemiboea albiflora is known from Maling River Valley and Pogang Nature Reserve, Xingyi City, Guizhou, China, growing on rock faces near Maling River and near streams in Pogang Nature Reserve, at an elevation of ca. 720–970 m.

Phenology

Flowering occurs in August to October and fruiting in October to November.

Etymology

The specific epithet refers to the corolla colour of this new species.

Additional collection

CHINA. Guizhou: Xingyi City, Maling River Valley, ca. 950 m alt., 12 October 2018, X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017060 (PE), X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017062 (PE); Xingyi City, Maling River Valley, ca. 720 m alt., 12 October 2018, X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017057 (PE); Xingyi City, Maling River Valley, C.Y. Deng 3071 (XIN); Xingyi City, Pogang Nature Reserve, ca. 1000 m alt.,11 October 2018, X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017054 (PE), X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017055 (PE), X.G. Xiang, Z.W. Wu & Z.Y. Guo 2017056 (PE).

Proposed IUCN conservation status

To date, Hemiboea albiflora has two known populations of more than 300 and less than 1000 mature individuals, according to field observations. Both populations are endemic in karst areas and grow on rock faces or under forests near streams. The population, which is distributed in scenic spots and habitats, is susceptible to human activities, e.g. road construction or deforestation. The species is considered to be “Vulnerable” (VU D1) according to the IUCN Red List Criteria (IUCN 2017), based on Criterion D1 and population size, estimated to be fewer than 1000 mature individuals.

Acknowledgements

This study was supported by the National Natural Science Foundation of China (Grant no. 31370227, 31300181, 31670212), Special Funds for Traditional Chinese Medicine Industry (201407003), Major supporting funds for Characteristic subject of Qiannan Normal College for Nationalities (No. QNSY2018XK003) and the Natural Science Foundation of Guizhou Province of China ([2014]2156).

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