Sunday, June 21, 2020

[Botany • 2020] Loxostigma puhoatense (Gesneriaceae) • A New Species from North Central Vietnam


Loxostigma puhoatense N.D. Do, N.S. Ly, D.H. Nguyen & T.H. Le

in Lý, Nguyễn, Lê, ... et Maciejewski, 2020.

Abstract
Loxostigma puhoatense N.D. Do et al., sp. nov., a new species of Gesneriaceae, is described and illustrated from Pu Hoat Nature Reserve, Nghe An Province, Vietnam. This species is morphologically similar to L. dongxingensis and L. damingshanensis in the plant habit, indumentum system of vegetative and reproductive characters, shape of leaf blades, calyx, pistil but differs from the latter two by the abaxially reddish-purple leaf blade with pubescent along veins, lateral veins 11–19, shorter white to pale yellowish-white corolla (3.7–3.8 cm long) with purple-spotted and glabrous inside, longer abaxial stamens in 2–2.1 cm, shorter and densely glandular-puberulent ovary in 1–1.2 cm, and sparsely glandular-puberulent style. Data on distribution, ecology, phenology, and vernacular of the new species are provided.

Keywords: Briggsia, Didymocarpus, Gesneriaceae, Loxostigma, taxonomy, Vietnam


Figure 1. Loxostigma puhoatense (from the holotype).
A mature plant with flowers B a part of stem C inflorescence D dorsal view of flower E opened flower showing stamens F gynoeciums G detail of stigma (from dry specimen) H infructescence I seeds.
Drawn by Ba-Vuong Truong from Do Ngoc Dai, Nguyen Danh Hung, Le Thi Huong, DHH 1021.

Figure 2. Loxostigma puhoatense.
 A plant in natural habitat B apical part of flowering plant showing inflorescences (with flowers and young fruits) and leaves C inflorescence D abaxial leaf E adaxial leaf F flower (from below) G flower (top view) H flower (front view) I longitudinal section with upper lip removed J stamens with gynoecium and calyxes K dried fruits.
Photos by Ngoc-Dai Do, plate by Ngoc-Sam Ly.

Loxostigma puhoatense N.D. Do, N.S. Ly, D.H. Nguyen & T.H. Le, sp. nov.

Diagnosis: This species is most similar to L. dongxingensis and L. damingshanensis in the plant habit, indumentum system of stem, leaves, shape of leaf blades, calyx and pistil but differs from the latter two in the leaf blade with abaxially reddish-purple and number of lateral veins, longer peduncle, shorter white to pale yellowish-white corolla with purple-spotted inside, longer abaxially stamens that are lower adnate above corolla tube base, shorter and glandular-puberulent ovary, and sparsely glandular-puberulent style.

Distribution and habitat: Loxostigma puhoatense is currently known from a single population with eight mature plants, in tropical evergreen broad-leaf forests, Pu Hoat Nature Reserve, Nghe An Province. More data is needed to determine conservation status. It is an epiphytic plant (Fig. 2A), growing on the surface of Ficus sp. (Moracaeae), and is associated with fern (e.g. Asplenium nidus L. (Aspleniaceae), epiphytic herbs (e.g. Aeschynanthus acuminatus Wall. ex A. DC. (Gesneriaceae), Pothos chinensis (Raf.) Merr. (Araceae) and is dominated by Beilschmiedia ferruginea H.Liu, Cinnamomum polyadelphum (Lour.) Kosterm., C. tamala (Buch.-Ham.) T.Nees & Eberm., Lithocarpus balansae (Drake) A. Camus, Syzygium grande (Wight) Walp., S. odoratum (Lour.) DC., Gordonia axillaris (Roxb. ex Ker Gawl.) Endl…

Etymology: The specific epithet “puhoatense” is derived from the type locality.

Vernacular name: Vietnamese language: Xuyến thư pù hoạt


     


 Ngọc-Sâm Lý, Danh-Hùng Nguyễn, Thị-Hương Lê, Minh-Hợi Trần, Ngọc-Đài Đỗ, Bá-Vương Trương and Stephen Maciejewski. 2020. Loxostigma puhoatense (Gesneriaceae), A New Species from North Central Vietnam. PhytoKeys. 151: 49-57. DOI: 10.3897/phytokeys.151.49473