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| Aristolochia geantha Z.R. Guo & Y.Fan Wang, in Guo, Wang, Onyenedum et Li, 2025. 地花关木通 || taiwania.NTU.edu.tw/abstract/2071 |
Abstract
A new species of Aristolochiaceae, Aristolochia geantha Z.R. Guo & Y.Fan Wang, from Southwest China, is described herein. Detailed scientific illustrations, color figures, and a key are provided. The species is morphologically proximate to A. petelotii, but can be readily distinguished by its flat, cupuliform calyx limb, which adaxially covered with golden or rusty villous hairs, a velvety pink upper tube, unusually elongated peduncle, which extends from the basal lignified stems, and distinctive stripe patterns radiating from the throat to the calyx limb margin. Comparative assessments with other congeners are provided to establish its unique taxonomic status within the genus.
Keyword: Aristolochia austroyunnanensis, Aristolochia petelotii, cauliflorous, liana, morphology, Siphsia (Isotrema)
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| Aristolochia geantha A. Habit, illustrating flowers on the ground, B. Young stem with leaves, C–D. Adaxial and abaxial views of the leaf, E. Inflorescence, F. Floral bud, G. Interior structure of the perianth, H–I. Gynostemium. Scale bars are provided in each panel accordingly. Line drawing by Yushan Cai. |
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| Morphological comparison I. A–D. Aristolochia geantha; E–H. A. petelotii; I–L. A. austroyunnanensis. A, E & I. Frontal view of the flowers; B, F & J. Frontal view of the buds; C, G & K. Longitudinal dissection showing the adaxial side of the perianth; D, H & L. Lateral view of the buds. Scale bars for each image are shown at the bottom left of each figure panel; all scale bars = 5.0 cm. |
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| . Morphological comparison II. A–D. Aristolochia geantha; E–H. A. petelotii; I–L. A. austroyunnanensis. A, E, I. Close-up of limb and throat; B, F, J. Gynostemium; C, G, K. Adaxial leaf lamina; D, H, L. Abaxial leaf lamina. Scale bars in B, F, J = 5.0 mm; scale bars in C, D, G, H, K, L = 5.0 cm. |
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| Illustration of Aristolochia geantha. A. Plant in situ, with flowers prostrate on the ground, throat facing upward, B. Habitat in situ, C. Adaxial view of the leaves, D. Abaxial view of the leaf, E. Bud, frontal view, F. Longitudinal section of the flower, G. Close-up of the gynostemium, H. Inflorescence showing elongated peduncle, I. Cyme bearing two flowers. Scale bars are provided in each panel accordingly. |
Aristolochia geantha Z.R. Guo & Y.Fan Wang, sp. nov.
Type: CHINA. Yunnan: Malipo County, Mali Township, ..., elevation 1338.5 m, ...
Diagnosis: Aristolochia geantha is similar to A. petelotii O.C.Schmidt (1933: 95) and A. austroyunnanensis S.M. Hwang (1981: 228) in having ovate to lanceolate leaf blades with acuminate apices, cordate bases, and rusty villous hairs on both surfaces, as well as a perianth with a concave, fused calyx limb of similar coloration. However, A. geantha can be readily distinguished by its flat cupuliform calyx limb, radiating stripes from the throat to the limb margin, densely long rusty or golden villous hairs on the adaxial surface of the calyx limb, a pinkish beige to pink throat, and a pink upper tube. Notably, this species exhibits a unique floral positioning behavior, characterized by an elongated peduncle emerging from the basal stem, placing the flower prostrate on the ground with the throat facing upward—a trait not observed in any other species within subgenus Siphisia. See Figs. 1–2, S1–2 and Table 1 for detailed comparisons.
Etymology: The epithet “geantha” conveys the
species’ distinctive inflorescence arrangement, based on
extensive field observations and cultivated living
collections. The flowers are borne on an unusually
elongated peduncle, which extends from the basal
lignified stems and positions the flowers directly upon the
ground, demonstrating a cauliflorous habit. This
arrangement, where the flowers rest on the substrate, is
not documented in any other taxa within the subg.
Siphisia, and the epithet is intended to highlight this
unique growth habit.
Vernacular name: During our fieldwork, we learned
that Aristolochia geantha, along with the sympatric
species A. petelotii, has long been used as a folk medicine
and is occasionally traded in markets under the vernacular
name “xuě shàng cǎo” (雪上草), which translates to
“growing above the snow.” However, this vernacular
term lacks clarity in reflecting the biological properties or
traits of the plants and functions as an umbrella name that
may refer to multiple Aristolochia subg. Siphisia taxa,
including A. petelotii. Based on the distinct characteristics
of A. geantha, we propose the Chinese name “dì huā guān
mù tōng” (地花关木通) to accurately reflect its growth
habit and ensure alignment with its scientific identity.
Zi-Rui Guo, Yi-Fan Wang, Joyce G. Onyenedum and Jing Li. 2025. Aristolochia geantha (Aristolochiaceae), A New Species from Yunnan, China. Taiwania. 70(2); 293-300. DOI: 10.6165/tai.2025.70.293 taiwania.NTU.edu.tw/abstract/2071
