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| Hoya lamthanhiae V.T. Pham & Kloppenb., in Pham, Kloppenburg, Averyanov, et al. 2020. |
Hoya lamthanhiae V.T. Pham & Kloppenb. is described and illustrated. The molecular data is provided; this species was found in Dak Lak province, southern Vietnam. Diagnostic features of the new species are a milky latex lithophytic vine and pure white with red-purple centre flowers. The described species clearly differs from closely related H. hainanensis in number of characters: a leaf blade shortly attenuated and wavy margins at the base, a hairy abaxial leaf surface, a bigger calyx with few sparse hairs or glabrous, a bigger corolla with acute lobe, shorter pollinia, as well as molecular characters.
Key words: Asclepiadoideae, Hoya, New species, Plant diversity, Vietnam.
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| Hoya lamthanhiae V.T. Pham & Kloppenb. A. Habit. B. Inflorescence with leaf (preserved in ethanol). C, D. Inflorescence. E. Leave (above: adaxial view; dorsal: abaxial view). F. Petioles. G. Leaf bases. H. A part of peduncle and pedicels. I. Flowers (left: frontal view; right: dorsal view). J. Corolla and corona (side view). K. Calyx and petal (view from behind). L. Corolla (frontal view and dorsal view). M. Corona (haft-side view). N. Corona lobe (left: half-side view; right: dorsal view). O. Ovary. P. Pollinaria. Q. Pollinia. R. Retinaculum. All illustrations were made from the type specimens. |
Hoya lamthanhiae V.T. Pham & Kloppenb., sp. nov.
Diagnostic morphology characters: Described species is most closely related to Hoya hainanensis Merr. (1923: 263) from Hainan, sometimes regarded as a synonym of H. ovalifolia Wight & Arn. (Li et al., 1995). However, type specimens of H. ovalifolia accessed from E and NY virtual herbariums and a description from Wight (1834: 37) are apparently quite different. In contrast, leaf form and habit of H. hainanensis is similar to the new species. The examination by the second author of type specimens of H. hainanensis deposited at UC and observations of other types at A, MO and US virtual herbariums, reveal the following differences from our new species; leaf blade shortly attenuate and wavy margins at base, hairy abaxial leaf surface, bigger calyx with few sparse hairs or glabrous, bigger corolla with acute lobe, as well as shorter pollinia as it is presented in Table 3.
Distribution: The species is currently known only from the lone type locality in Dak Lak province, southern Vietnam.
Habitat and ecology: Hoya lamthanhiae occurs in primarily evergreen broad-leaved forests, often on granite outcrops along streams at an elevation of approximately 800 m a.s.l.
Etymology: Species is named after its discoverer - Mrs. Lam Thi Ngoc Thanh.
Vernacular name: Vietnamese: Cẩm cù lâm thành.
The Van Pham, Robert D. Kloppenburg, L.V. Averyanov, et al. 2020. Hoya lamthanhiae (Asclepidoideae, Apocynaceae), A New Species from southern Vietnam. Pakistan Journal of Botany. 52(1); DOI: doi.org/10.30848/PJB2020-1(32)