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| Begonia barosma X.X. Feng, Y.N. Huang & Z.X. Liu, in Feng, Chen, Liu, Huang, Liu, Li, Zhao et Guo, 2023. |
ABSTRACT
Begonia barosma, a new species in Begonia sect. Coelocentrum Irmscher (Begoniaceae) from limestone karsts across Sino-Vietnamese border is described in detail. It shows high similarities to the adjacently distributed B. lanternaria Irmscher, but differs from it in fleshy, relatively flat leaf blade with different pattern of variegation, sparsely pilose on abaxial surface of outer tepals. The molecular phylogenetic analysis based on ITS supports that the new species is a monophyletic lineage, separating from B. lanternaria Irmscher. Considering its small population size, narrow distribution, and disturbance by human activities, its conservation status is categorized as “Vulnerable (VU B1, B2 ab (iv, v), C2 a (i), D2)” according to the IUCN Red List Categories and Criteria.
KEY WORDS: Begonia lanternaria, China, Guangxi, ITS, limestone karst, morphology, new taxon, Sino-Vietnamese Border.
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| Begonia barosma A. Habitat; B. Stipules; C. Abaxial leaf blade; D1-D3. Bracts; E. Front view of staminate flower showing 4 tepals; F. Back view of staminate flower showing 4 tepals; G. Lateral view of staminate flower; H. Androecium; I. Stamen; J. Front and back views of pistillate flower; K. Lateral view of pistillate flower; L. Cross section of ovary; M. Style; N, O. Stigma; P. Capsule. drawn by Yun Xiao Liu. |
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| Habitat and morphology of Begonia barosma. A. Habit and Habitat; B. Flowering plant; C. Creeping rhizome; D. Petiole; E. Adaxial leaf blade; F. Lateral leaf blade; G-J. Abaxial leaf blade showing relatively flat surface; K. Juvenile leaf; L. Stipules; M. Inflorescence; N,O. Bracts; P. Front and back views of staminate flower; Q. Stamens; R. Front and back views of pistillate flower; S. Lateral view of pistillate flower; T. Style and stigma; U. Cross sections of ovary; V. Mature capsule; W. Dry capsule showing placenta (Photos: Z.X. Liu). |
Begonia barosma X.X. Feng, Y.N. Huang & Z.X. Liu, sp.
nov.
Diagnosis: Begonia barosma morphologically
resembles B. lanternaria in rhizome and flower
characters. However, it differs from the latter in having
fleshy, relatively flat leaf blade which is adaxially
blackish-green along main veins, randomly silver white
between the veins, abaxailly purple-red and densely
pilose along main veins, pale green between the veins. In
addition, the new species also can be distinguished from
B. lanternaria in sparsely pilose on abaxial surface of
outer tepals.
Etymology: The specific epithet “barosma” refers to the
extreme sweet smell of the flower during blooming season.
Vernacular name: 醉香秋海棠
Xin-Xin Feng, Yan-Man Chen, Jian-Xun Liu, Yu-Ni Huang, Zhi-Xian Liu, Ren-Kun Li, Tong Zhao and Wei Guo. 2023. Begonia barosma, A New Species in Begonia sect. Coelocentrum (Begoniaceae) from Limestone Karsts across Sino-Vietnamese Border. Taiwania. 68(2); 349-354 DOI: 10.6165/tai.2023.68.349
