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 : 248-265

publication ID

https://doi.org/10.5852/ejt.2025.1022.3093

persistent identifier

https://treatment.plazi.org/id/0383878F-FF91-FF83-FD79-FE6B72E36C10

treatment provided by

Plazi

scientific name

Polyalthia chiangmaica Wiya, Damth. & Chaowasku
status

 

Genus Polyalthia Blume View in CoL

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

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.

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).

Polyalthia miliusifolia Wiya, Chanthamrong & Chaowasku sp. nov. urn:lsid:ipni.org:names:77365545-1 Figs 1 View Fig , 4–5 View Fig View Fig , 12 View Fig ; Table 2

Diagnosis

Morphologically most similar to P. minima , but differs mainly from it in several features (indumentum on young twigs and lower leaf midrib, flowering pedicel length, outer petal shape and apex, number of carpels per flower and stigma shape) as shown in Table 2.

Etymology

The leaves of the new species look somewhat similar to those of certain species of Miliusa Lesch. ex A.DC. (de Candolle 1832), e.g., M. astiana Chaowasku & Kessler ( Chaowasku & Kessler 2014), M. fragrans Chaowasku & Kessler ( Chaowasku & Kessler 2013), M. fusca Pierre ( Pierre 1881) and M. parvifolia (Kurz) Damth. & Chaowasku ( Damthongdee & Chaowasku 2022; basionym: Kurz 1875); hence, its specific epithet.

Type material

Holotype THAILAND • Cult. in Nakhon Si Thammarat Province (originally from Chalae Subdistrict, Thong

Pha Phum District, Kanchanaburi Province); Jul. 2022; fl.; Chanthamrong 74; holotype: CMUB [CMUB004000901]; isotypes: PBM, QBG.

Paratypes THAILAND • same data as for holotype; Nov. 2020; fl.; Chaowasku 228; QBG same data as for preceding; Nov. 2022; fl.; Chaowasku 233; QBG same data as for preceding; Jul. 2023; fl.; Chanthamrong 75; QBG .

Description

Treelets ca 0.6 m tall; young twigs villous with appressed and erect hairs. Petiole 1.0–2.0 mm long, indumentum similar to that of young twigs, slightly grooved above; leaf blade chartaceous, elliptic, rarely elliptic-obovate, 3.7–7.5 × 1.4–2.6 cm, almost glabrous above, villous with appressed and erect hairs below, base obtuse-subcordate to rounded-subcordate, rarely obtuse, apex ±acute, rarely obtuse, rounded or caudately short-acuminate; midrib slightly sunken above, villous with erect hairs, raised below, villous with appressed and erect hairs; secondary veins 7–10 per side, rather indistinct below, angle with midrib 60°–70° (at middle part of leaf blade). Inflorescences 2- or 3-flowered, terminal; peduncle and rachis (when present) inconspicuous; pedicel 1.8–2.0 mm long, velvety with appressed and erect hairs, bearing 1 ovate-triangular bract. Sepals free, broadly ovate to ±transversely ovate, 1.0–1.2 × 1.1–1.8 mm, outside and margin velvety with appressed and erect hairs, inside glabrous. Outer petals broadly ovate to subcircular, 2.3–3.0 × 1.9–2.5 mm, outside tomentose with appressed hairs, margin tomentose with appressed and erect hairs, inside almost glabrous, apex obtuse to rounded; inner petals ±cream in vivo at maturity, ovate-elliptic to elliptic-oblong, 6.8–7.5 × 3.0– 3.5 mm, outside tomentose with appressed hairs, margin tomentose with mostly appressed hairs, inside almost glabrous, apex obtuse to rounded. Stamens ca 28 per flower, 1.0– 1.1 mm long, connective apex truncate, covering thecae. Carpels 3 per flower, ca 1.5 mm long; stigmas globose; ovaries tomentose with appressed hairs; ovule 1 per ovary, basal. Torus depressed subglobose. Fruit unknown.

Habitat (at original locality) and phenology

The new species occurs in dry evergreen forests, near a stream. The elevation (at original locality) is ca 450 m. Flowering material was collected in July and November.

Distribution

Kanchanaburi Province, southwestern Thailand.

Preliminary conservation assessment

Data Deficient (DD).

Polyalthia esanensis Wiya, Damth. & Chaowasku sp. nov. urn:lsid:ipni.org:names:77365546-1 Figs 1 View Fig , 6–7 View Fig View Fig , 12 View Fig ; Table 3

Diagnosis

Morphologically most similar to P. chantaranothaii and P. acuminatissima sp. nov. (another new species described below; = P. evecta -4), but can be chiefly distinguished from the two by different combinations of traits (indumentum on young twigs, leaf texture, length of leaf acumen and outer petal length) as shown in Table 3.

Etymology

Named after ʻEsanʼ, an informal name for eastern and northeastern regions of Thailand where this species occurs.

Type material

Holotype

THAILAND • Amnat Charoen Province, Chanuman District, Khok Kong Subdistrict ; Jul. 2019; fl.; Chaowasku 225; holotype: CMUB [CMUB004001101]; isotype: QBG.

Paratypes

THAILAND • Udon Thani Province, Nong Saeng District, Thap Kung Subdistrict ; Jul. 2019; fl., fr.; Chaowasku 226; QBG same data as for holotype; May 2022; fl., young fr.; Chaowasku 230; QBG .

Description

Treelets ca 1.5 m tall; young twigs tomentose-villous to villous, hairs erect only or appressed and erect. Petiole 2.0–4.0 mm long, velvety with mostly erect hairs, slightly grooved above; leaf blade chartaceous, elliptic to obovate, sometimes narrowly obovate, 7.9–15.8 × 2.5–4.3 cm, puberulous with appressed hairs above, puberulous-tomentose intermixed with pilose below, hairs appressed only or appressed and erect, base obtuse-subcordate to rounded-subcordate, rarely obtuse, apex caudately short-acuminate (acumen 6.0–9.0 mm) to acute-acuminate, rarely acute to obtuse; midrib slightly sunken to flat above, tomentose-villous with erect hairs, raised below, velvety with appressed and erect hairs; secondary veins 8–13 per side, rather distinct below, angle with midrib 50°–70° (at middle part of leaf blade). Inflorescences 1- to 4-flowered, terminal (developing to internodal or ±leaf-opposed); peduncle and rachis (when present) inconspicuous; pedicel 5.0–11.0 mm long, velvety with appressed and erect hairs, bearing 1 ovate-triangular bract. Sepals free, broadly ovate, 2.5–3.0 × 2.6–3.1 mm, outside and margin velvety with appressed and erect hairs, inside glabrous. Outer petals ovate to ovate-triangular, 5.5–5.8 × 3.0– 3.2 mm, outside tomentose with mostly appressed hairs, margin tomentose with appressed and erect hairs, inside glabrous, apex acute; inner petals ± pale yellow in vivo at maturity, ovate to ovate-elliptic, 9.7–10.5 × 3.8–4.2 mm, outside and margin tomentose with mostly appressed hairs, inside almost glabrous, apex ±acute. Stamens 60–84 per flower, 1.2–1.6 mm long, connective apex truncate, covering thecae. Carpels 7–13 per flower, 1.8–2.0 mm long; stigmas ± obovoid; ovaries tomentose with appressed hairs; ovule 1 per ovary, basal. Torus depressed subglobose. Each fruit consisting of up to 6 monocarps which are ±subglobose, 5.5–7.0 × 5.3–6.0 mm, smooth and puberulous with mostly appressed hairs, apex not apiculate, stipe 5.5–7.0 mm long, often slightly obliquely attached to monocarps, indumentum similar to that of monocarps but a bit denser; fruiting pedicel ca 17.0 mm long. Seed 1 per monocarp, subglobose, ca 6.0 × 5.5 mm.

Habitat and phenology

The new species occurs in partially disturbed deciduous forests, near a stream. The elevation is 150– 570 m. Flowering and fruiting material was collected in May and July.

Distribution

Eastern and northeastern Thailand.

Preliminary conservation assessment

Data Deficient (DD).

Polyalthia acuminatissima Wiya, Damth. & Chaowasku sp. nov. urn:lsid:ipni.org:names:77365547-1 Figs 1 View Fig , 8–9 View Fig View Fig , 12 View Fig ; Table 3

Diagnosis

Morphologically most similar to P. chantaranothaii and P. esanensis sp. nov., but principally differs from the two by different combinations of features (indumentum on young twigs, leaf texture, length of leaf acumen and outer petal length) as shown in Table 3.

Etymology

The specific epithet refers to the usually distinctly elongated leaf apex.

Type material

Holotype

THAILAND • Nakhon Phanom Province, Ban Phaeng District, Phai Lom Subdistrict ; May 2022; fl., fr.; Chaowasku 231; holotype: CMUB [CMUB004001001]; isotypes: BK, CMUB, PBM, QBG.

Paratype

THAILAND • Nakhon Phanom Province, Ban Phaeng District, Phu Langka National Park ; 17°57′00″ N, 104°09′44″ E; elev. 150 m; 25 Aug. 2001; fr.; Pooma et al. 2617; L GoogleMaps .

Description

Treelets 1–2 m tall; young twigs puberulous intermixed with pilose, hairs appressed and erect. Petiole 1.5–4.0 mm long, puberulous with mostly appressed hairs, slightly grooved above; leaf blade chartaceous-subcoriaceous, narrowly elliptic to narrowly elliptic-obovate, rarely narrowly obovate, 12.3–20.2 × 2.3– 4.8 cm, glabrous above, puberulous with appressed hairs below, base obtuse-subcordate to obtuse, apex ± caudate-acuminate [acumen (12.0–)16.0–26.0 mm long] to acute-acuminate; midrib slightly sunken above, glabrous, raised below, puberulous with appressed hairs; secondary veins 10–16 per side, rather distinct below, angle with midrib 45°–70° (at middle part of leaf blade). Inflorescences 1- to 4-flowered, terminal (developing to internodal or ±leaf-opposed); peduncle and rachis (when present) inconspicuous; pedicel 4.5–11.0 mm long, puberulous intermixed with pilose, hairs mostly appressed, bearing 1 ovate-triangular bract. Sepals free to nearly half-connate, broadly ovate to ± transversely ovate-triangular, 2.2–3.5 × 2.8–3.5 mm, outside and margin puberulous-tomentose with appressed hairs, sparser at basal half, inside glabrous. Outer petals ovate to ovate-triangular, 4.5–5.5 × 2.2–3.2 mm, outside puberulous with appressed hairs, margin puberulous with appressed and erect hairs, inside glabrous, apex acute to acute-obtuse; inner petals ±pale yellow in vivo at maturity, 10.4–11.0 × 3.2–4.0 mm, (narrowly) ovate to (narrowly) ovate-elliptic, outside and margin puberulous with mostly appressed hairs, inside glabrous to almost glabrous, apex acute-obtuse to obtuse. Stamens 67–75 per flower, 1.3–1.6 mm long, connective apex truncate, covering thecae. Carpels 4–11 per flower, 2.0– 2.5 mm long; stigmas ellipsoid-obovoid to obovoid; ovaries tomentose with appressed hairs; ovule(s) 1 (rarely 2) per ovary, basal when containing 1 ovule and lateral when containing 2 ovules. Torus elevated, flat-topped. Each fruit consisting of up to 10 monocarps which are subglobose to subglobose-ellipsoid, 5.5–8.0 × 4.5–6.5 mm, smooth and shortpuberulous with mostly appressed hairs, apex short-apiculate, stipe 4.0–6.0 mm long, always attached obliquely to monocarps, indumentum similar to that of monocarps but a bit denser; fruiting pedicel to 11.0 mm long. Seed(s) 1 (rarely 2) per monocarp, ± subglobose (but flattened on one side when there are two seeds in a monocarp), ca 6.5 × 5.5 mm.

Habitat and phenology

The new species occurs in dry evergreen forests. The elevation is 150– 180 m. Flowering material was collected in May. Fruiting material was collected in May and August.

Distribution

Nakhon Phanom Province, northeastern Thailand.

Preliminary conservation assessment

Data Deficient (DD).

Polyalthia maxwelliana Wiya, Chanthamrong & Chaowasku sp. nov. urn:lsid:ipni.org:names:77365548-1 Figs 1 View Fig , 10–12 View Fig View Fig View Fig ; Table 4

Diagnosis

Morphologically most similar to P. khaoyaiensis , but primarily differs from it in several traits (leaf texture, flowering pedicel length, inner petal shape and number of carpels per flower) as shown in Table 4.

Etymology

The specific epithet honors James Franklin Maxwell (1945–2015), an extraordinary collector of Thai plants. Besides, he was the first curator and one of the founders of the herbarium CMUB.

Type material

Holotype THAILAND • Cult. in Nakhon Si Thammarat Province (originally from Chalae Subdistrict, Thong

Pha Phum District, Kanchanaburi Province); Aug. 2020; fl.; Chanthamrong 73; holotype: CMUB [CMUB004000801]; isotype: QBG.

Description

Treelets 1.5–4 m tall; young twigs tomentose-villous with mostly erect hairs. Petiole 2.5–3.5 mm long, indumentum similar to that of young twigs, grooved or slightly so above; leaf blade subcoriaceous, elliptic, rarely elliptic-obovate, 13.0–22.0 × 4.1–6.1 cm, almost glabrous above, puberulous with appressed hairs below, base obtuse-subcordate to rounded-subcordate, apex caudate-acuminate (acumen 10.0–20.0 mm long), sometimes acute-acuminate, rarely acute-obtuse; midrib slightly sunken above, tomentose-villous with mostly erect hairs, raised below, puberulous with appressed and erect hairs; secondary veins 11–17 per side, distinct below, angle with midrib 50°–60° (at middle part of leaf blade). Inflorescences 1- or 2-flowered, terminal developing to ± leaf-opposed; peduncle inconspicuous; pedicel 13.0–15.0 mm long, ± velvety with appressed and erect hairs, bearing 1–2 bract(s), ± triangular. Sepals free, ± transversely ovate, 4.0–4.5 × 4.5–6.0 mm, outside and margin puberulous-tomentose with appressed and erect hairs, slightly denser on apex, inside glabrous to almost glabrous. Outer petals ovate, 6.8–7.8 × 4.2–5.2 mm, outside and margin tomentose with appressed hairs, inside glabrous, apex ±acute; inner petals yellow-orange in vivo at maturity, ± broadly ovate, 16.0–17.0 × 11.5–13.0 mm, outside puberulous-tomentose to tomentose, hairs appressed, margin tomentose with mostly appressed hairs, sparser on basal half, inside puberulous-tomentose with appressed hairs only near margin on apical half, remaining area glabrous, apex acute-obtuse. Stamens ca 151 per flower, 2.2–2.5 mm long, connective apex truncate, covering thecae. Carpels ca 63 per flower, 4.2–4.6 mm long; stigmas elongated-obovoid; ovaries tomentose-villous with appressed hairs; ovule(s) 1 (rarely 2) per ovary, basal when containing 1 ovule and lateral when containing 2 ovules. Torus elevated, flat-topped. Fruit unknown.

Habitat (at original locality) and phenology

The new species occurs in dry evergreen forests with bamboos, near a stream. The elevation (at original locality) is ca 450 m. Flowering material was collected in August.

Distribution

Kanchanaburi Province, southwestern Thailand.

Preliminary conservation assessment

Data Deficient (DD).

Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF