Artabotrys spathulatus 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 : 74-77

Artabotrys spathulatus J.Chen, Chalermglin & R.M.K.Saunders sp. nov. Fig. 2

Diagnosis.

Similar to Artabotrys tanaosriensis J.Chen, Chalermglin & R.M.K.Saunders except with flat (vs. undulate) outer petal blades, broadly rhomboid (vs. broadly ovate) outer petal claws, broadly spathulate and strongly concave (vs. rhomboid and undulate) inner petal blades and strongly beaked monocarps.

Type.

THAILAND: Krabi Province, Mueang Krabi District, Phruksa Sawan limestone hill, 100 m elev., 15 Mar 2015, P. Chalermglin 580315 (holotype: BKF!; isotypes: L!, QBG!).

Description.

Climbers, to 20 m in height. Twigs drying brown, glabrous to sparsely hairy. Leaf laminas 9.6-18.1 cm long, 3-4.5 cm wide, oblong-elliptic, apex acuminate, base cuneate or decurrent, chartaceous, subglabrous both ab- and adaxially; midrib glabrous to sparsely hairy abaxially, glabrous adaxially, prominent and raised on both surfaces; secondary veins 6-14 pairs per leaf, visible on both surfaces; tertiary venation reticulate, visible on both surfaces; petioles 2-6 mm long, ca. 1 mm in diameter, glabrous to sparsely hairy. Inflorescence hooks recurved, laterally compressed, with 1 or 2 flowers; flowering pedicels ca. 10 mm long, ca. 1 mm in diameter, subgla brous. Sepals 4-5 mm long and wide, triangular, subglabrous both ab- and adaxially, venation indistinct. Outer petals with externally distinct blades and claws; blades 8-10 mm long, 7-8 mm wide, deltoid, flat, sparsely hairy both ab- and adaxially; claws ca. 5 mm long and wide, broadly rhomboid, densely hairy abaxially, glabrous adaxially. Inner petals with externally distinct blades and claws; blades 6-7 mm long, 4-5 mm wide, broadly spathulate, strongly concave, sparsely hairy both ab- and adaxially; claws ca. 5 mm long, ca. 3 mm wide, narrowly rhomboid, densely hairy abaxially, glabrous adaxially. Stamens numerous per flower, ca. 1 mm long, ca. 1 mm wide; apex of connectives truncate. Carpels ca. 30 per flower, ca. 1 mm long, ca. 1 mm wide; ovaries ovoid; stigmas ellipsoid, extending centrifugally. Fruiting pedicels unknown. Monocarps (in fresh material) up to 30 per fruit, 19-26 mm long, 14-18 mm wide, obovoid, strongly beaked (beak ca. 2 mm long), sessile. Seeds 2 per monocarp, plano-convex, 12-14 mm long, 9-11 mm wide.

Phenology.

Flowering and fruiting specimens collected in March.

Distribution and habitat.

So far only known from Thailand (Fig. 5 ). Inhabits tropical rain forests at the base of limestone hills; ca. 100 m elev.

Etymology.

The specific epithet reflects the morphology of the inner petals.

Local name.

Karawek Phruksa Sawan.

Notes.

The fruit and seeds are only known from fresh material and have not been preserved due to fungal infection.

The distinction between A. spathulatus and A. tanaosriensis is corroborated by unpublished phylogenetic analysis of combined chloroplast (matK, ndhF, psbA-trnH, trnL-F) and nuclear (AP3, carboxymethylenebutenolidase, GI, HMGS, LFY, mag1, ncpGS, NIA, PhyA, RPB2) DNA sequence data, which retrieved A. spathulatus as sister to A. uniflorus , with A. tanaosriensis sister to A. suaveolens (J. Chen et al. unpublished data).

New records for Thailand

Figures

Figure 2. Artabotrys spathulatus. A Flower with flat outer petal blades and broadly spathulate and strongly concave inner petal blades B Inflorescence with hooked peduncle and flower with externally distinct inner petal claw and blade C Fruit with distinctly beaked monocarps D Flower with externally distinct outer petal blade and claw E Leaves and habit (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 /).