Amischotolype balslevii Boonsuk, Chantar. & Kantachot, 2024

Amischotolype balslevii Boonsuk, Chantar. & Kantachot , sp. nov. — Fig. 1 View Fig , 2 View Fig ; Map 1 View Map 1

Nodes puberulent to glabrous;leaf sheaths,lower surface of pseudo-petioles, sepals and filaments glabrous;sepals 10–14 mm long;fruits ellipsoid, 16–18 mm long, purple-white. — Type: B. Boonsuk 896 ( holotype KKU!; isotype AAU!, QBG!), Thailand, Udon Thani, Ban Dung district, Ban Dung subdistrict, N17°42'34" E103°12'47", 183 m alt., 19 July 2021 GoogleMaps .

Etymology. The name of this species honours Professor Henrik Balslev, Aarhus University, Denmark, who encouraged the authors to conduct research on the Commelinaceae for the Flora of Thailand Project.

Herbs, ascending, decumbent or scrambling; nodes puberulent to glabrous; internodes 6.5–10 cm long, glabrous, green. Leaf sheaths 4 – 5 by 1–1.2 cm, glabrous, mouth ciliate. Leaf blades elliptic-lanceolate, 24– 32 by 4.5 –8 cm, base cuneateattenuate, margin entire, apex acuminate-caudate; upper surface dark green, glabrous except for the whitish submarginal hairs, 0.2 – 0.3 mm long; lower surface pale green, glabrous; pseudo-petioles 1.5 – 2 by 0.9 –1.2 cm, slightly winged, margin minutely ciliate, lower surface glabrous. Inflorescences with 12 – 16 flowers, densely grouped, ovoid, 3 –5.5 by 2 –2.5 cm, borne on decumbent or scrambling stems, glabrous; inflorescence bracts ovate, c. 5 by 4 mm, apex acute, glabrous; bracteoles ovate, c. 5 by 4 mm, margin entire, glabrous. Sepals 10–14 by 3 – 4.5 mm, light green with pink or violet tip (in flower) to pink- ish purple (in fruit), glabrous, with hooded tip. Petals oblongoblanceolate, 7– 8 by 3– 3.5 mm, white. Stamens: filaments 9 –11 mm long, white, glabrous; anthers oblong, 1.8–1.9 by 1–1.8 mm, white, longitudinally dehiscent. Ovary obconical, 2.7– 3 by 1.5 –1.7 mm; styles 10–12 mm long, white; stigma simple. Capsule ellipsoid, 16 –18 by 8 –9 mm, exceeding the sepals by 5 – 9 mm, purplish white, apex obtuse and slightly depressed, distally densely hairy, hairs 0.5 –1 mm long, style remnant present. Seeds 2 per locule, with orange aril, 6.5 –7 by 3.5 – 4 mm (without aril), with a ventral groove.

Distribution — Thailand (NE: Loei, Udon Thani, Nakhon Phanom, SE: Chon Buri, Chanthaburi), Lao PDR (Bolikhamxai, Khammouane) (see also under the notes and Map 1 View Map 1 ).

Habitat & Ecology — Along open streams, nearby waterfall, in moist exposed area in gallery forest or in disturbed evergreen forest.

IUCN threat status — Amischotoype balslevii has no record of utilization and was mostly found in conserved forests in Thailand and also in Lao PDR. Its population is stable enough in these habitats, it should be rated as Least Concern (LC) based on the IUCN Standards and Petitions Committee (2022).

Vernacular name — Muang si udon (ม่ วงศรีอุดร).

Additional specimens examined ( paratypes). LAO PDR, Khammouane, Nakai , Oudom Souk, 3 Apr. 2005, Svengsuksa et al. 32 (BKF); Bolikhamxai, Tha Phabat, Tad Leuk Waterfall, 31 May 2006, Newman et al. 1935 (BKF) . – THAILAND, Loei, Na Haeo, 20 June 1995, Nanakorn et al. 3805 (QBG) ; Udon Thani, Ban Dung district , Ban Dung subdistrict, 25 Apr. 2022, Boonsuk 935 (AAU, KKU, QBG) ; Nakhon Phanom, Ban Phaeng , Phu Langka NP, 25 Aug. 2001, Pooma et al. 2619 (BKF) ; Chonburi, Khao Khiao Opened Zoo, 9 Sept. 2000, Phengklai 12932 (BKF) ; Chanthaburi, Khao Khitchagut NP, Krathing Waterfall , 7 June 2000, Thitimetharoch 331 (BKF,KKU); Laem Sing, Namtok Phlio NP, 4 Apr. 1971, Maxwell 71­251 (BK); ibid., 26 Mar. 1972, Maxwell 72­155 (AAU, BK); ibid., 13 Oct. 1972, Maxwell 72­317 (AAU, BK) .

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Notes — 1. Amischotolype balslevii is distinctive in having puberulent stem nodes, leaf sheaths and blades, a brownish ciliate sheath mouth, 0.2–0.3 mm long submarginal hairs on the upper leaf surface, and the largest capsules within the genus, which are purplish white and 16–18 mm long and attached to and protruding from the sepals. The sepals are glabrous, 10 –14 mm long, hooked, succulent, and persistent in fruiting ( Fig. 1 View Fig , 2 View Fig ). The sepals and capsules of this species are the largest in the genus in Asia based on Duistermaat (2012). The new species shared some morphological characters with A. divaricata , a common Asian species, and A. gracilis , a Malaysian/Indonesian species, in that they have green to purple sepals (when young) that are shorter than the capsules, as well as hairy fruits. It differs from the first in having puberulent to glabrous nodes, glabrous leaf sheaths and glabrous lower leaf surface, larger sepals and capsules, and ovoid and purplish white fruits. It can be distinguished from the latter by having shorter and different coloured submarginal hairs ( 0.2– 0.3 mm long, whitish vs 1–2.5 mm long, yellowish brown), longer sepals, glabrous filaments, and longer and ellipsoid capsules (see also Table 1).

2. In Thailand, it is found disjunctly in provinces of Northeastern Thailand ( Loei, Udon Thani, and Nakhon Phanom), as well as in provinces of Southeastern Thailand ( Chonburi and Chanthaburi), in moist areas such as along streams or near waterfalls. It has not been recorded from Eastern Thailand, possibly due to a lack of collection in this region. Additionally , the two specimens from Lao PDR (Bolikhamxai and Khammouane) are from locations near NE Thailand, show that the new species is also present in Lao PDR ( Map 1 View Map 1 ) .