Volume 16 > Part 1 > Year 2022 > Page 217 > Annonaceae > Monoon

18. Monoon roseum Bunchaleewfo-1000040841

Thai Forest Bull., Bot. 50(1): 16. 2022. Plate XXVI: C–D.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Tree up to 10 m tall, bark brownish grey, furrowed, with knobs. Twigs pubescent with conspicuous lenticels. Leaves chartaceous, asymmetrically oblanceolate or oblong, 10.5‒18 by (3.7–)4.5‒7.5 cm, base asymmetrically cuneate to obtuse, apex acuminate, the acumen 7‒15 mm long, glabrous on both surfaces except for hairs along the midrib and lateral veins, midrib grooved above, secondary veins fairly straight, 10‒12 per side, tertiary venation percurrent; petioles 5‒8 mm long, flat above, pubescent. Inflorescences forming fascicles in axils of leafless twigs and on woody tubercles of trunks, 2‒5-flowered, pedicels 25‒35 mm long, 2‒2.2 mm thick, pubescent, each bearing one adnate ovate bract 1.5‒2 by 1.5‒1.7 mm between the base and the midpoint; buds ovoid. Sepals valvate, free, thinly coriaceous, triangular, 6‒8 by 3‒4 mm, apex acute and recurved, pubescent outside and glabrous inside. Petals imbricate at the apices, incurved, pale pink to red, thinly coriaceous, ovate, apex acute, puberulous outside and glabrous inside, longitudinal veins conspicuous; outer petals 30‒35 by 10‒12 mm, base with claw 4–5 mm long; inner petals 28‒33 by 12‒15 mm, base with claw 5–7 mm long. Stamens cuneate, 1‒1.2 mm, anther connective apex truncate. Carpels numerous, 1.5‒1.8 mm long, pubescent, stigmas higher than anther connective apices, clavate, 0.6‒0.7 mm long, pubescent. Receptacle cushion-shaped, 4‒5 mm in diam., 1.5‒2 mm thick, pubescent. Fruit of up to 25 monocarps borne on a pedicel 30‒55 mm long, 2.5‒3 mm thick. Monocarps red to black when mature, oblongoid, 2.2‒2.5 by 1.2‒1.5 cm, smooth, glabrous, apex and base obtuse, stipe 40‒55 mm long, 2‒2.2 mm thick; pericarp less than 1 mm thick. Seeds oblongoid, 20‒22 by 10‒12 mm, light brown, smooth, slightly shiny.

Thailand : PENINSULAR: Ranong (Khao Phota Chong Dong – type: Kerr 16740, holotype -BK), Surat Thani (Ban Ta Khun), Phangnga (Kopa, Khao Phlai Bang To), Nakhon Si Thammarat (Ban Khiriwong, Khao Luang), Trang (Khao Chet Yot).

Distribution : Endemic.

Ecology : Tropical rain forests, 150‒660 m alt. Flowering: November‒March; fruiting: February–April.

Vernacular : Ka nan (กานัน)(Phangnga).

Notes: Specimens of Monoon roseum have formerly been misidentified as M. hookerianum (King) B.Xue & R.M.K.Saunders or M. glabrum (King) B.Xue & R.M.K.Saunders, having a similar appearance when dried. Monoon glabrum is not known from Thailand; M. hookerianum has yellow flowers and a pedunculate inflorescence.