Artabotrys tanaosriensis J.Chen, Chalermglin & R.M.K.Saunders, 2018

Chen, Junhao, Chalermglin, Piya & Saunders, Richard M. K., 2018, Two new species and two new records of Artabotrys (Annonaceae) from Thailand, PhytoKeys 95, pp. 71-81 : 73-74

Artabotrys tanaosriensis J.Chen, Chalermglin & R.M.K.Saunders sp. nov. Fig. 1

Diagnosis.

Similar to Artabotrys oblanceolatus Craib except with cuneate or decurrent (vs. rounded) leaf base, symmetrical (vs. asymmetrical) leaf base, externally distinct outer petal blades and claws, deltoid and undulate (vs. ovate and flat) outer petal blades, rhomboid and undulate (vs. ovate and flat) inner petal blades, shorter monocarps (1.5-2 cm vs. 2-2.5 cm), slightly beaked (vs. sharply beaked) monocarps and monocarps with shorter stipes (ca. 2 mm vs. ca. 4 mm).

Type.

THAILAND: Phetchaburi Province, Kaeng Krachan National Park, Phanoen Thung Ranger Station, 1000 m elev., 25 Aug 2004, I.C. Nielsen 1911 (holotype: L! [barcode L 3729228]; isotype: AAU, n.v.; SING! [barcode SING 0115634]).

Description.

Climbers, to 20 m in height. Twigs drying grey-brown, glabrous to sparsely hairy. Leaf laminas 9.5-15.5 cm long, 2.3-4.0 cm wide, oblong-elliptic, apex acuminate, base cuneate or decurrent, chartaceous, glabrous both ab- and adaxially; midrib glabrous to sparsely hairy abaxially, glabrous adaxially, prominent and raised on both surfaces; secondary veins 8-12 pairs per leaf, visible on both surfaces; tertiary venation reticulate, visible on both surfaces; petioles 2-5 mm long, ca. 1 mm in diameter, glabrous to sparsely hairy. Inflorescence hooks recurved, laterally compressed, with 1-3 flowers; flowering pedicels 7-9 mm long, ca. 1 mm in diameter, glabrous. Sepals ca. 4 mm long, 4-6 mm wide, triangular, subglabrous both ab- and adaxially, venation indistinct. Outer petals with externally distinct blades and claws; blades 10-12 mm long, 7-8 mm wide, deltoid, undulate, sparsely hairy both ab- and adaxially; claws ca. 4 mm long, 6-8 mm wide, broadly ovate, densely hairy abaxially, subglabrous adaxially. Inner petals with externally distinct blades and claws; blades 7-10 mm long, 4-5 mm wide, rhomboid, undulate, sparsely hairy both ab- and adaxially; claws ca. 6 mm long, ca. 4 mm wide, rhomboid, densely hairy abaxially, glabrous adaxially. Stamens ca. 90 per flower, ca. 1 mm long, ca. 1 mm wide; apex of connectives truncate. Carpels 24-30 per flower, ca. 1 mm long, ca. 1 mm wide; ovaries ovoid; stigmas ellipsoid, extending centrifugally. Fruiting pedicels 10-11 mm long, ca. 2 mm wide, glabrous. Monocarps 8-30 per fruit, 15-20 mm long, 9-13 mm wide, ellipsoid, glabrous, slightly beaked (beak less than 1 mm long), drying with longitudinal ridges, subsessile or with stipes up to ca. 2 mm long. Seeds 2 per monocarp, plano-convex, ca. 16 mm long, ca. 8 mm wide.

Phenology.

Flowering specimens collected in February and August; fruiting specimens collected in October.

Distribution and habitat.

So far only known from Thailand (Fig. 5 ), but possibly also occurring in the adjacent Tanintharyi National Park in Myanmar. Inhabits tropical rain forests on lateritic soil; 150-1000 m elev.

Etymology.

The specific epithet alludes to "Tanao Sri", the Thai name of the Bilauktaung subrange of the Tenasserim Range where this species occurs.

Local name.

Karawek Tanao Sri.

Additional specimens examined (paratypes).

Thailand: Prachuap Khiri Khan Province, Hua Hin District, Huai Sat Yai, Pa La-U Village, 17 Oct 2016, P. Chalermglin 591017 (BKF, HKU, L, QBG); Phetchaburi Province, Kaeng Krachan District, Huai Mae Phriang Village, 14 Feb 2015, P. Chalermglin 580214 (BKF, HKU, L, QBG).

Figures

Figure 1. Artabotrys tanaosriensis A Flower with undulate petal blades and narrow constriction at the junction between petal blades and claws B Flower with rhomboid inner petal blades C Fruit with weakly beaked monocarps D Habit E Leaves (Photos: P. Chalermglin).

Figure 5. Distributions of A. byrsophyllus, A. punctulatus, A. spathulatus and A. tanaosriensis in Thailand and surrounding areas. Localities of A. byrsophyllus in Peninsular Malaysia were retrieved from Turner and Utteridge (2015). Localities of A. punctulatus in Yunnan were retrieved from georeferenced herbarium records in GBIF (https: // www. gbif. org /).