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| Monoon roseum Bunchalee, in Bunchalee, Johnson & Murray, 2022. กานัน || DOI: 10.20531/tfb.2022.50.1.02 |
Abstract
The widespread Asian genus Monoon (Annonaceae) comprises about 70 tropical forest species, over 20 of which occur in Thailand. Four new species from Thailand are described here: Monoon roseum and M. ornithocephalum from Peninsular Thailand and M. phukraduengense and M. phuluangense from North-Eastern Thailand.
Keywords: New species, Peninsular Thailand, North-Eastern Thailand, Polyalthia
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| หนังหนาหัวนก Monoon ornithocephalum Bunchalee |
Monoon ornithocephalum Bunchalee, sp. nov.
Monoon ornithocephalum resembles M. fuscum, differing in the absence of an inflorescence peduncle, the oblanceolate petals, and the asymmetrically oblongoid or ellipsoid monocarps 15–20 mm wide with stipes 15–18 mm long (Table 1). In contrast, M. fuscum has inflorescence peduncles 2–4 mm long, oblong petals, and symmetrically ovoid monocarps 10–12 mm wide with stipes 3–5 mm long.
Thailand.— SOUTH-WESTERN: Prachuap Khiri Khan [Kui Buri National Park]; PENINSULAR: Surat Thani [Khlong Phanom National Park].
Ecology.— Tropical rainforest, 100–700 m.
Etymology.— Monoon ornithocephalum is named for the shape of the monocarp, which resembles a bird’s head.
Vernacular.— Nang na huai nok (หนังหนาหัวนก).
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สะบันงาภูกระดึง Monoon phukraduengense Bunchalee สะบันงาภูหลวง Monoon phuluangense Bunchalee |
Monoon phukraduengense Bunchalee, sp. nov.
Monoon phukraduengense resembles M. laui (Merr.) B.Xue & R.M.K.Saunders in texture and size of leaves and flower parts when dried, number of secondary veins, and the thickness of pedicels, but differs in its asymmetrical elliptic to oblanceolate leaves, cuneate to broadly cuneate leaf bases, oblong petals 35–40 × 7–9 mm, and flower pedicels 25–30 × 1.8–2 mm (Table 2). It is also similar to M. phuluang-ense but is distinguished from that species by the inflorescences only 1–4-flowered, glabrous pedicels 25–30 mm long, valvate sepals, petals green to yellowish green and tinged with purplish red on the inner base, and carpels 1–1.2 mm long.
Thailand.— NORTH-EASTERN: Loei [Phu Suan Sai National Park; Phu Kradueng National Park].
Ecology.— Hill evergreen forest or semi-evergreen forest, 700–1,222 m.
Etymology.— The specific epithet refers to the type locality.
Vernacular.— Saban nga phukradueng (สะบันงาภูกระดึง).
Monoon phuluangense Bunchalee, sp. nov.
Monoon phuluangense differs from both M. laui and M. phukraduengense in having longer pedicels ((30–)35–50(–60) mm), elliptic-oblong to oblong outer petals (29–)35–43 × 8–10 mm, and inner petals that are elliptic or curved on one side and 40–45 × 10–12 mm (Table 2). Monoon phuluangense further differs from M. phukraduengense in having inflorescences with up to 10 flowers, pubescent pedicels, glabrous sepals, petals yellow to reddish yellow with conspicuous red veins, and carpels 1.5–1.8 mm long.
Thailand.— NORTH-EASTERN: Loei [Phu Luang Wildlife Sanctuary].
Ecology.— Hill evergreen forest with oak trees, in sandy soil, 1,000–1,400 m.
Etymology.— The specific epithet refers to the type locality.
Vernacular.— Saban nga phuluang (สะบันงาภูหลวง).
Notes.— Monoon phuluangense and M. phukraduengense, both species of higher-elevation habitats in North-Eastern Thailand, are compared, along with M. laui, in Table 2. Monoon phuluangense also somewhat resembles M. roseum, but the petals of M. phuluangense are yellow with red markings and are not attenuate at the base.
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| Monoon roseum Bunchalee. A. habit, showing old inflorescence bases on trunk; B. immature and mature leaves on twigs; C & D. flowers; E. mature monocarps; F. lower surface of leaf; G. upper surface of leaf; H. longitudinal section of monocarp and seed. Photographs taken at Ban Kiriwong, Kam Lon, Lan Saka District, Nakhon Si Thammarat Province, A‒E on 25 March 2015, F‒H from Bunchalee 162 (KKU), collected from the same site on 26 April 2000. |
Monoon roseum Bunchalee, sp. nov.
Monoon roseum resembles M. hookerianum (King) B.Xue & R.M.K.Saunders and M. glabrum (King) B.Xue & R.M.K.Saunders but differs from both species in the fasciculate inflorescence, pale pink to red ovate petals, and monocarp stipes 40–55 mm long, versus pedunculate monochasial cymes, yellow oblong, oblanceolate, or obovate petals, and monocarp stipes 25–40 mm long.
Thailand.— PENINSULAR: Ranong; Surat Thani; Nakhon Si Thammarat [Ban Kiriwong; Khao Luang National Park]; Trang [Khao Chetyot].
Ecology.— Tropical rainforest, 150–660(–1,200) m.
Etymology.— The specific epithet refers to the pale pink to red colour of the flowers, unusual in the genus.
Vernacular.— Ka nan (กานัน) (Phangnga).
SUMMARY:
The new Monoon species described here are the only species of the genus known to be endemic to Thailand. Monoon phukraduengense and M. phuluangense occur in a small area of the North-Eastern Region. The other native Monoon species known from this Region, M. obtusum, M. simiarum and M. viride (Craib) B.Xue & R.M.K.Saunders, are more common and widely distributed. In the Peninsular Region, M. ornithocephalum and M. roseum bring the total number of described native species for the Region to 14 and the Monoon diversity for Thailand to 20 described native species.
Pasakorn Bunchalee, David M. Johnson and Nancy A. Murray. 2022. Distinctive New Monoon Species (Annonaceae) from Thailand, increasing Diversity of A Genus of Ecologically Important Asian Trees. Thai Forest Bulletin (Botany). 50(1); ; 9–19. DOI: 10.20531/tfb.2022.50.1.02
