Three new species of Polyalthia (Annonaceae) from Thailand and Laos Author Bunchalee, Pasakorn 0000-0001-8644-3360 pasakorn @ msu. ac. th; https: // orcid. org / 0000 - 0001 - 8644 - 3360 pasakorn@msu.ac.th Author Johnson, David M. 0000-0003-2896-7419 Department of Botany and Microbiology, Ohio Wesleyan University, Delaware, Ohio, 43015, USA & dmjohnso @ owu. edu; https: // orcid. org / 0000 - 0003 - 2896 - 7419 dmjohnso@owu.edu Author Murray, Nancy A. 0000-0003-4076-6169 Department of Botany and Microbiology, Ohio Wesleyan University, Delaware, Ohio, 43015, USA & namurray @ owu. edu; https: // orcid. org / 0000 - 0003 - 4076 - 6169 namurray@owu.edu Author Chalermglin, Piya 0000-0002-9098-0916 Agricultural Technology Department, Thailand Institute of Scientific and Technological Research, 35 Mu 3, Khlong Ha, Khlong Luang District, Pathum Thani Province 12120, Thailand & piya. chalerm @ gmail. com; https: // orcid. org / 0000 - 0002 - 9098 - 0916 piya.chalerm@gmail.com text Phytotaxa 2021 2021-07-29 512 4 272 282 http://dx.doi.org/10.11646/phytotaxa.512.4.3 journal article 10.11646/phytotaxa.512.4.3 1179-3163 5315278 Polyalthia chayamaritana P.Bunchalee & N.A.Murray , sp. nov. , ( Figs. 5 , 6 ) Type :— THAILAND . Roi Et , Nongpok Dist. , Phu Khiao , Tham Pha Nam Thip Non-Hunting Area , 16° 23´40.55˝ N , 104° 18´37.16˝ E , 375 m , 17 Aug 2015 , Puudjaa , Rueangruea & Hemrat 1897 ( holotype BKF210578 !) . Polyalthia chayamaritana resembles P. cinnamomea in petiole length, leaf shape, and axillary inflorescences but differs in being a short tree with the primary leaf vein flat on adaxial surface, inflorescence with a distinct peduncle and rachis, narrowly lanceolate to linear-lanceolate petals 13.0–25.0 × 2.0–4.0 mm, and 2 ovules per carpel. In contrast, P. cinnamomea is a medium to tall tree with the primary vein grooved on the adaxial surface, inflorescence lacking a peduncle and rachis, linear petals 55.0–90.0 × 3.0–7.0 mm, and 4 ovules per carpel. Small trees 1.0–3.0 m tall, d.b.h. up to 3.5 cm , primary branching spiral; bark smooth, blackish gray. Twigs rusty brown erect-tomentose, lenticels moderately conspicuous. Leaves with petioles 4.0–5.0 mm long, 1.8–2.0 mm thick, grooved above, erect-tomentose; lamina symmetrically narrowly elliptic, 13.0–22.0 × 3.0– 5.5 cm , base asymmetrically cordate with auricles 0.3–0.5 mm long, apex acute, upper side glabrous, lower side erect-puberulous; midrib flat above, densely erect-pubescent; lateral veins curved towards the apex, 14–16 veins per side, attached excurrently to midrib at 65–70º, mixed eucampto/brochidodromous, curving inward 2.0–4.0 mm from margins; interlateral veins present; tertiary veins weakly percurrent. Inflorescences 1–2(–4)-flowered, axillary on leafy twigs or on woody tubercles of trunk or leafless twigs, peduncles 1.0−2.0 mm long; rachis 2.0−4.0 mm long, 1.5−2.0 mm thick; pedicels 1.0–2.0 mm long, 1.2−1.5 mm thick, brown erect-tomentose; bract lanceolate, 3.5–5.0 × 2.0– 2.5 mm , attached at the pedicel base, appressedtomentose outside, glabrous inside; buds lanceoloid. Sepals pale brown, ovate, valvate, 4.0–5.0 × 3.5–4.5 mm , apex acute, appressed-tomentose outside, glabrous inside. Petals 6 in 2 whorls, pale greenish brown to pale pinkish brown or pale greenish white in vivo , narrowly lanceolate, valvate, appressed-tomentose outside, glabrous inside; outer petals 14.0–25.0 × 3.0–4.0 mm, apex acute; inner petals 13.0–23.0 × 2.0– 2.5 mm , apex acute. Stamens pale creamy white at anthesis, cuneate, 1.3−1.5 × 0.8−1.0 mm; anthers 1.0– 1.2 mm long; anther connective apex truncate; androecium 4.0– 4.5 mm in diameter. Carpels 7–20 per flower, 1.8–2.0 × 0.4–0.5 mm , appressed-pubescent; style subsessile; stigma globose, 0.4–0.5 mm in diameter, erect-puberulous, higher than anther connective apices; ovules 2 per carpel. Torus convex and truncate, 1.8–2.0 mm in diameter, 1.0– 1.2 mm thick, glabrous. Fruits of up to 12 monocarps borne on a pedicel up to 10.0 mm long, 1.8–2.0 mm thick; monocarps brown when ripe, subglobose or oblongoid, 8.0–12.0 × 8.0–10.0 mm, appressed-tomentose, apex blunt, stipes 1.0–2.0 mm long, 0.8–1.0 mm thick. Seed 1(–2) per monocarp, subglobose or strongly biconvex, discoid, 6.0–8.0 mm in diameter, surface pitted and surrounded by a longitudinal groove, light brown, shiny; endosperm ruminations spiniform, endosperm glass like. Ecology: —Known only from moist mountain slopes in dry evergreen forest at 250–375 m . Phenology: —Flowering February−March and August, fruiting March–June and August. Local name: —Thai: thon ammarit (ต้นอัมฤทธิ์). Etymology: —In honour of Kongkanda Chayamarit, expert on the Thai flora and executive editor of the Flora of Thailand project. Conservation status: —The conservation status is proposed as Data Deficient. Polyalthia chayamaritana is only known from the eastern Khorat Plateau, in the Tham Pha Nam Thip Non-Hunting Area, Nongpok District, Roi Et Province . Notes: — Polyalthia chayamaritana has distinctive pale pink guava-scented wood, a feature shared with Polyalthia cinnamomea , a species distributed from Peninsular Thailand southward. Polyalthia chayamaritana is the only cauliflorous Polyalthia species known from the Khorat Plateau.