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| Actinostephanus F.Wen, Y.G.Wei & L.F.Fu Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin in Wen, Xin, Hong, Cai, Chen, ... et Fu, 2022. |
Abstract
Actinostephanus, a new genus from southern China, is described and colorfully illustrated with a single species, A. enpingensis. This new genus is morphologically most similar to Boeica and Leptoboea, nevertheless, it can be easily distinguished from the latter two by the following characteristics, such as leaves in whorls of three, all closely clustered at the top; corolla bowl-shaped, 5-lobed, actinomorphic; capsule hard, oblong-ovoid, short, 3–4 mm long, densely appressed villous, wrapped by persistent densely pubescent calyx lobes, style persistent. The new genus and related genera were sequenced using the next-generation sequencing technique. The whole plastid genome of the new genus is 154, 315 – 154, 344 bp in length. We reconstructed phylogenetic trees using the dataset of 80 encoded protein genes of the whole plastid genome from 47 accessions based on ML and BI analyses. The result revealed that the new genus was recovering in a polytomy including Boeica, Rhynchotechum, and Leptoboea with strong support, congruent to the morphological evidence. A global conservation assessment was also performed and classifies A. enpingensis as Least Concern (LC). In addition, after a review of recently described species of Gesneriaceae, we propose that plant enthusiasts, especially Gesneriad fans, have been playing an increasingly important role in the process of new taxa-discoveries.
Keywords: Boeica, Didymocarpoideae, flora of China, IUCN, Leptoboea, phylogeny
Subfamily: Didymocarpoideae
Actinostephanus F.Wen, Y.G.Wei & L.F.Fu, gen. nov.
Diagnosis: Actinostephanus F.Wen, Y.G.Wei & L.F.Fu resembles two small genera, Boeica C.B.Clarke and Leptoboea Benth. according to the molecular evidence and some morphological data, but differs from the latter two by the following distinguishing characters: leaves in whorls of three, all closely clustered at the top; corolla bowl-shaped, 5-lobed, actinomorphic; capsule hard, oblong-ovoid, short, 3–4 mm long, densely appressed villous, wrapped by persistent densely pubescent calyx lobes, style persistent. The detailed distinguishing characters of this new genus and its congeners are listed in Table 1.
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| Photos of Actinostephanus F.Wen, Y.G.Wei & L.F.Fu gen. nov., the individuals in natural habitat. Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin sp. nov. A top view of plant B upward view of plant for showing root system C top view of bud at the end of root D upward view of bud at the end of root E adaxial surfaces of leaves F abaxial surfaces of leaves G cymes H lateral view of flower I posterior view of flower J frontal view of corolla K stamens and staminodes L abaxial surfaces of calyx lobes M pistil N infructescence O capsule and persistent calyx lobes P opened capsule Q cross-section of capsule R seeds. |
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| Actinostephanus F.Wen, Y.G.Wei & L.F.Fu gen. nov.(A. enpingensis F.Wen, Y.G.Wei & Z.B.Xin sp. nov.), the individuals in natural habitat. A habitat B habit C plant in flowering D plant in fruiting. |
Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin, sp. nov.
Etymology: The genus name, “Actinostephanus”, consists of two parts, both derived from the Greek. The front part, “Actino-” is derived from ἀκτῑ́ς (aktῑ́s, “ray, beam”), means radiating; the latter half, “-stephanus”, is derived from Στέφανος (Stéphanos, “crown”), is also closely associated in ᾰ̓́νθος (ánthos, “flower, blossom, bloom”), hints corolla. The combined Greek word-roots characterize the uncommon corolla characteristic of the new genus and species. The character of the corolla, in China’s Gesneriaceae, is rare. Only three species belonging to two genera were known to have actinoform corolla in China, namely Bournea sinensis Oliv., B. leiophylla (W.T.Wang) W.T.Wang & K.Y.Pan ex W.T.Wang and Oreocharis esquirolii H.Lév. before this new genus was discovered.
Vernacular name of the new genus
Chinese mandarin: Fú Guàn Jù Tái Shǔ (辐冠苣苔属).
Distribution and habitat: Endemic to Enping county, Guangdong province, China, under evergreen broadleaved forests in a montane mountain yellow soil area at 170–250 m altitude.
Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin, sp. nov.
Ecology: Plants of the new taxon were primarily accessible in the Qixingkeng provincial natural reserve, growing on nearly vertical or steep slopes of montane yellow soil under tropical evergreen broad-leaved forest. Voucher specimens were made in the usual way (Bridson and Forman 1998) from some accessible plants that could be reached from the type locality. The conservation assessment was prepared following IUCN (2019).
Fang Wen, Zi-Bing Xin, Xin Hong, Lei Cai, Xiao-Yun Chen, Jun-Jie Liang, Hui-Feng Wang, Stephen Maciejewski, Yi-Gang Wei and Long-Fei Fu. 2022. Actinostephanus (Gesneriaceae), A New Genus and Species from Guangdong, South China. PhytoKeys. 193: 89-106. DOI: 10.3897/phytokeys.193.80715
