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| Petrocodon gracilis T. Ding & B. Pan, in Ding, Liu, Zhang, Wang, Huang, Lin, Pan et Li, 2024. |
ABSTRACT
The genus Petrocodon is renowned for its remarkably diverse floral morphology, exhibiting a high level of disparity compared to most genera within Gesneriaceae. In this study, we present a detailed description and illustration of Petrocodon gracilis T. Ding & B. Pan, a new species with unique floral features that is native to Guangxi, China. This species is geographically close to P. jingxiensis H.S. Gao & W.B. Xu and is indistinguishable from P. jingxiensis in vegetative characteristics. However, it can be clearly distinguished from the latter by its shorter pedicels, slender tubular corolla, shorter corolla tube, distinctly unequal corolla lobes with upper ones linear and reflexed and lower ones oblanceolate, and included chiritoid-like stigma. The presence of linear upper lobes and the chiritoid-like stigma has not been previously reported in Petrocodon, and the emergence of this new species will further expand the morphospace occupied by this morphologically diverse genus.
Keywords: disparity, floral morphology, Gesneriaceae, pollination taxonomy
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| Petrocodon gracilis: (a) habitat, (b) habit, (c) inflorescence, (d) corolla in the front view, (e) corolla in the side view, (f) longitudinal section of the corolla, (g) capsule, (h1) stigma in a bud, and (h2–h4) stigmas in opening flowers. |
Petrocodon gracilis T. Ding & B. Pan, sp. nov.
Diagnosis: The new species is most similar to P. jingxiensis but can be distinguished from the latter by the short pedicels of 1–4 mm long (vs. long pedicels 10–22 mm), a slender tubular corolla (vs. narrowly funnel-shaped corolla), a short corolla tube of 8–12 mm long (vs. a long corolla tube of 15–25 mm long), distinctly unequal corolla lobes with the upper ones linear and reflexed and the lower ones oblanceolate (vs. subequal ovate corolla lobes with the upper ones erect), and included stigma (vs. exserted stigma).
Etymology: The species epithet is derived from the almost linear upper corolla lobes. The Chinese name given is Xi Ban Shi Shan Ju Tai (细瓣石山苣苔).
Tao Ding, Ming Liu, Qiang Zhang, Peng-Fei Wang, Xing Huang, Yan-Xiang Lin, Bo Pan and Peng-Wei Li. 2024. Petrocodon gracilis (Gesneriaceae), A New Species from southwestern Guangxi, China. Ecology and Evolution. 14(12); e70670. DOI: doi.org/10.1002/ece3.70670
