Research Article |
Corresponding author: Xin Hong ( hongxin200710084@126.com ) Academic editor: Wen-Hong Chen
© 2020 Wei-Hua Qin, Dong-Dong Ding, Zhong-Lin Li, Yun-Feng Gao, Shu Li, Xin Hong.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Qin W-H, Ding D-D, Li Z-L, Gao Y-F, Li S, Hong X (2020) Oreocharis flavovirens, a new species of Gesneriaceae from Southern Gansu Province, China. In: Shui Y-M, Chen W-H, Ren M-X, Wen F, Hong X, Qiu Z-J, Wei Y-G, Kang M (Eds) Taxonomy of Gesneriaceae in China and Vietnam. PhytoKeys 157: 101-112. https://doi.org/10.3897/phytokeys.157.31732
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Oreocharis flavovirens is a new species of Gesneriaceae from Gansu, China and is described and illustrated here. It is morphologically similar to O. glandulosa, O. humilis and O. farreri, but those congeners of this new taxon can be distinguished by several salient characters. A description of O. flavovirens, together with illustrations and photos, are presented.
Gansu of China, new taxon, Oreocharis
In the summer of 2018, two of the authors (QWH and GYF) encountered an unknown Gesneriaceae species with young flowers during a botanical survey in Gansu Province. Subsequently, the plants were monitored in the field and flowering specimens were collected in autumn. The gross morphology, such as leaves in a basal rosette with spiral leaf arrangement, shape of the corolla and pistil, including stigma, indicates that this taxon can be assigned to Oreocharis Benth., which now includes species from eleven former genera (
After thorough comparisons of diagnostic morphological and anatomical features of similar taxa from China, Vietnam and Thailand (
Measurements and morphological character assessments of the new species were performed and described, using specimens worked on by the authors. All available specimens of Oreocharis stored in the following herbaria in China, Russia, the United States and the United Kingdom were examined (codes according to Thiers 2015+): E, GH, IBK, K, KUN, MO, PE and US. In addition, images of other type specimens were obtained from Tropicos (http://www.tropicos.org) and JSTOR Global Plants (http://plants.jstor.org). All morphological characters were studied under dissecting microscopes and are described using the terminology presented by
Oreocharis flavovirens can be diagnosed as a new species from all others in the genus by the upturned corolla tube combined with its rare greenish-yellow colour.
CHINA. Gansu Province: Yuhe Provincial Nature Reserve, Longnan City, 33.08426°N, 105.27858°E, 1,193 m a.s.l., 5 September 2018, flowering, Xin Hong: HX18090510 (holotype: IBK; isotype: PE).
Perennial, rosette herbs. Leaves basal, spirally arranged, 4–20, petiolate; petioles terete, 1.4–4 cm long, ca. 2 mm in diameter, densely reddish-brown long woolly and white glandular hairy; leaf blades ovate to obovate or elliptic, 3–6 × 1.5–3 cm, bases cuneate, slightly unequal, margins crenate to lobulate, apices obtuse, papery, adaxially sparsely rust-brown villous hairy, green, abaxially densely brown villous along veins, pale green; midrib usually vivid when fresh, lateral veins 3–5 on each side of midrib, distinct, concave adaxially, prominent abaxially. Inflorescences cymes, axillary, 1–2(–3)-branched, 1–6(–10)-flowered; peduncles 4–10 cm long, pale green, densely white glandular hairy and sparsely brown pilose; pedicels 1–3(–5) cm long, with indumentum as on the peduncle. Bracts 2, ca. 3 × 1 mm, lanceolate, margins entire, green, glabrous inside, brown pilose and sparsely glandular hairy outside; bracteoles similar but smaller, ca. 1.5 × 0.5 mm. Calyx actinomorphic, 5- sect from base, segments oblong to linear-lanceolate, 2–3.5 × ca. 1.0 mm, green, glandular hairy outside and glabrous inside, margins entire, sometimes revolute when flowering. Corolla zygomorphic, ca. 2 cm long, greenish-yellow to greenish, lobes greenish, becoming white at tube base, outside densely glandular-pubescent, inside glabrous; tube cylindrical, dilated and slightly narrowing gradually ventricose from base to throat and constricted at the throat, ca. 15 mm long, ca. 3 mm in diameter at base and ca. 2 mm in diameter at the throat; limb slightly 2-lipped; adaxial lip rounded, 2.5–3 × ca. 3 mm, emarginate or rarely undivided, shorter than abaxial lip; abaxial lip 3-sect from above middle, lobes obovate to elliptic, apex rounded, central longer than laterals, 3× 4–ca. 3 mm. Stamens 4, adnate to corolla 1–4 mm above base, included; filaments slender, the long two ca. 8 mm long, the short two ca. 6 mm long, sparsely glandular-pubescent, free, white to greenish; anthers yellow, basifixed, coherent in pairs, thecae divergent at base, oblong, ca. 0.5 mm long, 2-loculed, dehiscing longitudinally from arcuate slits, connective not projecting, glabrous; staminode 1, glabrous, 0.5–1.5 mm long, adnate to 1 mm above corolla tube base. Disc ring-like, 1–1.5 mm high, glabrous, entire or subentire, greenish-yellow. Pistil 1–1.2 cm; ovary narrowly oblong, 1-loculed, ca. 1 cm long; placentas 2, parietal, projecting inwards, 2-cleft, style 1–2 mm long, glabrous; stigma orbicular, emarginated, ca. 2 mm in diameter. Capsules oblong lanceolate to oblanceolate, straight, 2–4 cm long, dehiscing loculicidally to base; valves 2, glabrous. Seeds unknown.
Morphological character of Oreocharis flavovirens Xin Hong A–B different sizes of leaves (A adaxial leaves B abaxial leaves) C indumentum of petiole D abaxial leaf blades, showing veins and indumentum E cyme and infructescence F bracts G dissection of a flower H opened corolla, showing stamens and staminodes I pistils without corolla, showing stigma J young capsule K disc and calyx revolute of the young capsule. Scale bars: 2 cm (A–C); 1.5 cm (D, E); 3 mm (F, I, K), 1 cm (G, H, J).
The specific epithet is derived from its greenish-yellow corolla.
To date, Oreocharis flavovirens is only found at the type locality, Yuhe Provincial Nature Reserve, Gansu Province, which is located at the intersection of the Qinling Mountains and the Minshan Mountains. This species grows amongst moss on moist shady surfaces of stones near waterfalls, at an elevation of 950–1200 m a.s.l. The average temperature is 21°C, the average annual precipitation has been calculated as ca. 780 mm. The forest is a subtropical evergreen broad-leaved forest.
As is known, Oreocharis Benth. is a genus (more than 120 species) in the angiosperm family Gesneriaceae, which are mainly distributed in southern and south-western China, at the same time with a few species extending into Vietnam, Myanmar, India, Bhutan, Japan and Thailand (
Obviously, the genus is special for its remarkable floral diversity and it has made this genus to be one of the most taxonomy-difficult groups in the family. The new species, Oreocharis flavovirens which has a light-yellow cylindrical corolla with a distinct upturned tube, is a good example. The shape of the corolla tube, cylindrical and upturned, is a distinct character that not many species in Oreocharis possess. If we only consider the similarity of corolla tube shape, it is close to Oreocharis tubiflora K.Y. Pan and O. argyreia Chun ex K.Y. Pan, including constriction at the mouth but the latter two are lacking the upturned corolla tube. Given the corolla shape, the corolla of several species of former Ancylostemon Craib are similar too, except the tubes are straight or slightly turned down, but not up, though the flowers are predominantly yellow (rarely pink in A. ronganensis K. Y. Pan=Oreocharis ronganensis (K.Y.Pan) Mich.Möller & A.Weber), but not greenish-yellow. On the other hand, the upturned tube is more reminiscent of former Opithandra wentsaii Z.Yu Li (=Oreocharis wentsaii (Z. Yu Li) M. Möller & A. Weber) and former Opithandra pumila (W.T.Wang) Wang (=Oreocharis pumila (W.T.Wang) Mich.Möller & A.Weber), only here the tubes of previous Opithandra are slightly more trumpet-shaped in dark pink or pink and have two fertile stamens rather than four (
Furthermore, although the genus Oreocharis was redefined to accommodate species with distinctive floral morphologies from ten other genera, based on molecular phylogenetic studies in the last two decades, the evolutionary trends of the floral characters have not yet been understood comprehensively. The major causes of the incongruence and conflict between classical taxonomy and molecular phylogenetic studies for Oreocharis s.l. remain largely unexplored. There are other similar examples in Gesneriaceae of Asian, for example, Primulina s.l. (
Gansu Province: Yuhe Provincial Nature Reserve, Longnan City, 24 September 2019, in fruit, Yun-Feng Gao et al.: WF19092401 (AHU).
Diagnostic character differences amongst Oreocharis flavovirens sp. nov., O. glandulosa, O. humilis and O. farreri.
Characters | Oreocharis viridifrons | O. glandulosa | O. humilis | O. farreri |
Shape of leaf blade | ovate to obovate or elliptic | lanceolate-ovate | elliptic to lanceolate | rhombic-ovate to obovate or elliptic |
Indumentum of leaf blade | adaxially sparsely rust-brown villous hairy | adaxially densely brownish villous | adaxially sparsely brown villous, glabrescent | gray pubescent |
Number of lateral veins on each side of midrib | 3–4 | 5–6 | 3–5 | 4–6 |
Size of Bracts | 3 mm | 5 mm | 2-4 mm | 3.5–5 mm |
Shape of tube | campanulate-tubular, laterally compressed at mouth | tubular to subcampanulate | tubular | campanulate-tubular |
Size of corolla | ca. 20 mm long | 10–15 mm long | 11–15 mm long | 9–11 mm long |
Color of corolla | greenish-yellow to greenish | pale purple | yellow-white | purple-pink to orange-pink |
Shape and size of adaxial lip | emarginate or rarely undivided, 2.5-3 mm | emarginate or rarely undivided, 4 mm | 2-lobed, 2 mm | emarginate |
size of abaxial lip | 3–4 mm, longer than to nearly equalling abaxial lip | 2 mm, shorter than to nearly equalling abaxial lip | 3.5 mm, longer than to nearly equalling abaxial lip | 2 mm, shorter than abaxial lip |
Staminodes | adnate to 1 mm above corolla tube base | adnate to 0.5 mm above corolla tube base | adnate to 3.5 mm above corolla tube base | adnate to 1 mm above corolla tube base |
Ovary | 10 mm | 3-7 mm | 6–8 mm | 4 mm |
Stigma | peltate, orbicular | emarginate | 2-lobed | oblate |
We thank Prof. Shui Yu-Min from Kunming Institute of Botany and Alisa Grabovskaya from Komarov Botanical Institute for helping to check the type specimens. Additionally, local forestry staff of Yuhe Provincial Nature Reserve are gratefully acknowledged for their long-term field exploration and considerable contributions to the conservation of the regional biodiversity. This study was financially supported by the Anhui Provincial Natural Science Foundation (1908085QC1), EMREF Scholarship Award of The Gesneriad Society, Anhui University Doctor Startup Fund, Key University Science Research Project of Anhui Province (No. KJ2017A022), Fund of Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain (No.19-050-6), Guilin Science and Technology Foundation (20180107-6) and Science Research Foundation of Guangxi Academy of Sciences (2017YJJ23022).