Hemiboea crystallina Y.M.Shui & W.H.Chen, 2018

Chen, Wen-Hong, Zhang, Ya-Mei, Li, Zhen-Yu, Nguyen, Quang-Hieu, Nguyen, Tien-Hiep & Shui, Yu-Min, 2018, Hemiboea crystallina, a new species of Gesneriaceae from karst regions of China and Vietnam, Phytotaxa 336 (1), pp. 95-99 : 95-97

Hemiboea crystallina Y.M.Shui & W.H.Chen , sp. nov. Fig. 1 .

Type: — CHINA. Yunnan: Malipo County, Tianbao, at the entrance of limestone cave on cliffs, 22°58’ 31’’ N, 104°47’06’’ E, elev. ca. 800 m, 19 November 2002, in flower, Y. M. Shui et al. 21812 (holotype KUN!, isotype PE!).

The new species is more similar to Hemiboea flaccida Chun ex Z.Y.Li than the other species of the genus with glabrous interior surface of corolla and absence of the ring of corolla tube, but it is different in glabrous stem, inflated nodes, glabrous and lanceolate leaves, involucre with four wide wings, calyx segments with reflected lobe margins and glabrous fruits.

Herbs, perennial, epipetric on limestone. Stems to 40 cm high, glabrous, with some inflated nodes. Leaves opposite, unequal to sub-equal in a pair; leaf blade lanceolate, 4.5–11.0 × 1.3–3.0 cm, glabrous, base attenuate to cuneate, margin repandcrenate, apex acuminate, midrib and lateral veins inconspicuous adaxially and protuberant abaxially, lateral veins 5–9 on each side; petiole 1–3 cm, glabrous. Cymes acrogenous, 1–2-flowered; peduncle 0.6–1.2 cm, glabrous; involucre ca. 2.0 cm in diameter, outside glabrous, with 2 connate opposite bracts and 4 wide wings on costas. Calyx actinomorphic, 5- sect from base; segments subequal, elliptic-lanceolate, 1.5–1.7 × 0.2–0.4 cm, glabrous, margin reflected, 3-veined. Corolla outside white, inside purplish-red, 3–4 cm long; tube funnel-form to tubular, not swollen on top, longer than corolla lobes, 2.6–3.2 cm long, ca. 0.7 cm in diam., pubescent outside; lobes 2-lipped, adaxial lip 2-lobed, lobes subequal, widely ovate, 0.6 × 0.7–0.8 cm, abaxial lip 3-lobed, lobes unequal, apex rounded, middle lobe major, widely ovate, ca. 0.6 × 0.8 cm, lateral 2, minor, slightly obliquely ovate, ca. 0.6 × 0.6–0.7 cm. Stamens 2, glabrous; filaments ca. 1.3 cm long, curved, adnate to abaxial side of corolla tube 1.4 cm above base; anthers basifixed, round, 1.3–1.5 mm in diameter, thecae parallel, not confluent at apex, dehiscing longitudinally; staminodes 2, 0.6–0.7 cm long, adnate to adaxial side of corolla tube ca. 1.5 cm above base. Disc ring-like, ca. 1 mm high. Ovary linear to cone-shaped, 9–10 mm long, 2–2.3 mm in diameter, 2-loculed only with fertile adaxial locule; placenta 1 and axile; stigma 1, 1.6–1.8 cm long, slightly obtuse, undivided. Capsule clavate, 2.4–2.8 cm long, glabrous.

Etymology: —The epithet refers to grow on surface of crystalline rocks of limestone cave.

Phenology: —Flowering in November; fruiting in December.

Notes: — Hemiboea crystallina is closely related to Hemiboea flaccida in the absence of the hair ring inside corolla tube, but differs mainly by the glabrous surface of stems and leaves. This new species is also similar to Hemiboea pingbianensis Z.Y.Li (1983: 383) in their surface of stems, but it differs in surface and margin of the leaves. Moreover, it is also similar to Hemiboea integra C.Y.Wu ex H.W.Li (1983: 27) in the surface of leaves, while it differs in the hair ring of corolla, the margin of leaves, the color of corolla and the number of staminodes. The characteristic comparisons are summarized in Table 1.

Additional Examined Specimens: — VIETNAM. Lao Cai: Bac Ha, Ta Van Chu comm., Tenh Chu village , limestone secondary forests, 22°36’28’’ N, 104°15’57’’ E, elev. 1533 m, 14 November 2009, in flower, CKF Team 162 [ KUN!, CPC! (Herbarium of the Center for Plant Conservation, Vietnam Union of Science and Technology Associations, Hanoi)] ; ibid, Su Manh Khang village , 22°35’21’’ N, 104°14’57’’ E, elev. 1411 m, 17 November 2009, in flower, CKF Team 217 ( KUN!, CPC!) ; ibid, 22°34’48’’ N, 104°15’27’’ E, elev. 1000 m, 15 November 2009, in flower, Y. M. Shui V-019 ( KUN!) ; ibid, 22°35’14’’ N, 104°15’31’’ E, elev. 1000 m, 17 November 2009, in flower, Y. M. Shui V-024 ( KUN!) .

Distributions and Conservation: —The new species only grows on cliffs in China or in limestone forests dominated by Caryota obtusa Griffith (1845: 480) in Vietnam, at elevation of 800 ‒ 1500 m in Malipo County of SE Yunnan, China, bordering northwestern Vietnam, and Bac Ha in Lao Cai of northwestern Vietnam. So far, there are about 20 mature individuals found in a little limestone cave (Crystal Cave) on the type locality (Malipo county, Yunnan province, China) and totally about 60 mature individuals in the limestone forests both in China and Vietnam. It is estimated that this species covers less than 10 square kilometers for the presently known two populations, and both the area of occupancy and quality of habitat are becoming to be reduced due to the tourism and road construction. Therefore, this species is suggested to be classified as Critically Endangered (CR) according to the IUCN standards ( IUCN 2001).

Figures

FIGURE 1. Hemiboea crystallina Y.M.Shui & W.H.Chen (photographed by Yu-Min Shui). A. Habitat; B. Plant; C. Part of stem showing inflated nodes (nd); D. Connate bracts with four wide wings on the involucre (bract; br); E. Corolla tube and calyx segments (ca) with reflected margin; F. Face view of corolla showing the glabrous surface at the mouth of corolla; G. Lateral view of opened corolla showing the interior surface of corolla tube, stigma and stamens; H. Bird view of opened corolla; I. Young fruits. Scale bars: A=10 cm; B, C, G. & H=2 cm; D=4 mm, E=16 mm, F=5 mm; I=1 cm. Note:A–H, Y. M. Shui et al. 21812 (KUN and PE); I. CKF Team 217 (KUN).