Polyalthia chiangmaica Wiya, Damth. & Chaowasku, 2025

Wiya, Chattida, Damthongdee, Anissara, Chanthamrong, Kithisak, Ue-Aree, Phasit & Chaowasku, Tanawat, 2025, Uncovering five new species of Polyalthia (Annonaceae, Miliuseae) from Thailand: molecular and morphological congruence, European Journal of Taxonomy 1022, pp. 243-276 : 248-251

publication ID	https://doi.org/10.5852/ejt.2025.1022.3093
DOI	https://doi.org/10.5281/zenodo.17370653
persistent identifier	https://treatment.plazi.org/id/0383878F-FF91-FF9D-FE5C-FE2472E368F3
treatment provided by	Plazi
scientific name	Polyalthia chiangmaica Wiya, Damth. & Chaowasku
status	sp. nov.

Treatment

Polyalthia chiangmaica Wiya, Damth. & Chaowasku sp. nov.

urn:lsid:ipni.org:names:77365544-1

Figs 1–3 View Fig View Fig View Fig , 12 View Fig ; Table 1 View Table 1

Diagnosis

Morphologically most similar to P. evecta and P. intermedia but differs mainly from them by different combinations of features (flowering pedicel and outer petal length, ratio of outer petal to inner petal length and number of carpels per flower) as shown in Table 1 View Table 1 .

Etymology

The specific epithet refers to Chiang Mai Province of northern Thailand where the new species occurs.

Type material

Holotype

THAILAND • Chiang Mai Province, Chiang Dao District, Chiang Dao Subdistrict ; Dec. 2021; fl., fr.; Chaowasku 229; holotype: CMUB [ CMUB004001201 ]; isotypes: BK, CMUB, PBM, QBG.

Paratype

THAILAND • Chiang Mai Province, Chiang Dao District, Chiang Dao Subdistrict ; Oct. 2022; fl., fr.; Chaowasku 232; QBG .

Description

Shrubs ca 6 m tall; young twigs tomentose-villous with appressed and erect hairs. Petiole 1.5–3.0 mm long, puberulous-pilose with mostly appressed hairs, slightly grooved above; leaf blade chartaceous, elliptic, rarely elliptic-obovate, 8.0–18.5 × 3.0– 7.6 cm, glabrous above, puberulous with appressed hairs below, base obtuse to obtuse-subcordate, apex acute to acute-obtuse, rarely obtuse; midrib slightly sunken above, puberulous with erect hairs, raised below, puberulous with appressed hairs; secondary veins 9–14 per side, rather distinct below, angle with midrib 55°–70° (at middle part of leaf blade). Inflorescences 1- to 4-flowered, terminal (developing to internodal); peduncle inconspicuous to 3 mm long; rachis ca 7 mm long when present, tomentose with appressed and erect hairs, with scars of fallen flowers; pedicel 6.5–8.0 mm long, puberulous intermixed with pilose, hairs appressed and erect, bearing 1 ovate-triangular bract. Sepals free, broadly ovate, 2.0–2.5 × 2.8–3.0 mm, outside and margin tomentose-villous with mostly appressed hairs, inside almost glabrous. Outer petals ovate to broadly ovate, 2.2–2.5 × 1.9–2.0 mm, outside tomentose with appressed hairs, margin tomentose with appressed and erect hairs, inside almost glabrous, apex ± acute; inner petals ± pale yellow-orange in vivo at maturity, elliptic-oblong, 7.5–8.2 × 4.5–5.0 mm, outside tomentose with appressed hairs, margin tomentose with appressed and erect hairs, inside glabrous, apex ± acute. Stamens ca 100 per flower, 1.3–1.5 mm long, connective apex truncate, covering thecae. Carpels 16–22 per flower, 1.7–1.9 mm long; stigmas obovoid; ovaries tomentose-villous with appressed hairs; ovule 1 per ovary, basal. Torus elevated, flat-topped. Each fruit consisting of up to 2 monocarps which are globose to subglobose, 6.0–7.5 × 6.0– 6.5 mm, smooth and puberulous-tomentose with mostly appressed hairs, apex short-apiculate, stipe 2.0– 5.5 mm long, sometimes slightly obliquely attached to monocarps, tomentose with appressed and erect hairs; fruiting pedicel to 20 mm long. Seed 1 per monocarp, subglobose, ca 6.3 × 5.8 mm.

Habitat and phenology

The new species occurs in secondary forests adjacent to dry evergreen forests, near a stream. The elevation is ca 500 m. Flowering and fruiting material was collected in October and December.

Distribution

Chiang Mai Province, northern Thailand.

Preliminary conservation assessment

Data Deficient (DD).