Polyalthia chayamaritana P. Bunchalee &amp; N. A. Murray 2021, sp. nov.
Creators: name: Bunchalee, Pasakorn
name: Johnson, David M.
name: Murray, Nancy A.
name: Chalermglin, Piya
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Magnoliales
Annonaceae
Polyalthia
Polyalthia chayamaritana

description: <i>Polyalthia chayamaritana</i> P.Bunchalee &amp; N.A.Murray, <i>sp. nov.</i>, (Figs. 5, 6) Type:— THAILAND. Roi Et, Nongpok Dist., Phu Khiao, Tham Pha Nam Thip Non-Hunting Area, 16° 23´40.55&amp;dblac; N, 104° 18´37.16&amp;dblac; E, 375 m, 17 Aug 2015, <i>Puudjaa, Rueangruea &amp; Hemrat 1897</i> (holotype BKF210578!). <i>Polyalthia chayamaritana</i> resembles <i>P. cinnamomea</i> 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, <i>P. cinnamomea</i> 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 <i>in vivo</i>, 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. <b>Ecology:</b> —Known only from moist mountain slopes in dry evergreen forest at 250–375 m. <b>Phenology:</b> —Flowering February−March and August, fruiting March–June and August. <b>Local name:</b> —Thai: <i>thon ammarit</i> (ต้นอัมฤทธิ์). <b>Etymology:</b> —In honour of Kongkanda Chayamarit, expert on the Thai flora and executive editor of the <i>Flora of Thailand</i> project. <b>Conservation status:</b> —The conservation status is proposed as Data Deficient. <i>Polyalthia chayamaritana</i> is only known from the eastern Khorat Plateau, in the Tham Pha Nam Thip Non-Hunting Area, Nongpok District, Roi Et Province. <b>Notes:</b> — <i>Polyalthia chayamaritana</i> has distinctive pale pink guava-scented wood, a feature shared with <i>Polyalthia cinnamomea</i>, a species distributed from Peninsular Thailand southward. <i>Polyalthia chayamaritana</i> is the only cauliflorous <i>Polyalthia</i> species known from the Khorat Plateau.
description: Published as part of <i>Bunchalee, Pasakorn, Johnson, David M., Murray, Nancy A. &amp; Chalermglin, Piya, 2021, Three new species of Polyalthia (Annonaceae) from Thailand and Laos, pp. 272-282 in Phytotaxa 512 (4)</i> on page 279, DOI: 10.11646/phytotaxa.512.4.3, http://zenodo.org/record/5315278