THAI FOREST BULL., BOT. 47(2): 171–183. 2019. DOI https://doi.org/10.20531/tfb.2019.47.2.07 Three new species, lectotypifications and synonymisations in Millettia (Fabaceae: Faboideae) for Thailand SAWAI MATTAPHA1,*, FELIX FOREST2, JULIE HAWKINS3, SOMRAN SUDDEE4, NAIYANA TETSANA4 & PRANOM CHANTARANOTHAI5 ABSTRACT During preparation of the account of the genus Millettia (Fabaceae: Faboideae) for the Flora of Thailand, some new field collections and specimens from herbaria were found to represent three new species, and here they are described and illustrated with a distribution map. Lectotypes of Millettia names are designated for nine species, five new synonyms ofMillettia are proposed and Millettia tecta is raised to species status. KEYWORDS: Generic circumscription, Leguminosae, Millettieae, taxonomy. Accepted for publication: 16 September 2019. Published online: 11 October 2019 INTRODUCTION within the tribe Millettieae remain poorly understood and the genus Millettia itself shares several important The genus Millettia Wight & Arn. belongs to characters with other closely related genera within the tribe Millettieae sensu Geesink (1984), a tribe the tribe (Hu et al., 2000). Recently, Schrire (2005) known to be not only particularly complicated has also suggested that the circumscription of a taxonomically, but polyphyletic in the family revised tribe is impossible unless the genera within Fabaceae (Doyle et al., 1997, 2000; Hu, 2000; Hu the tribe are more comprehensively sampled in et al., 2000, 2002; Kajita et al., 2001; Wojciechowski phylogenetic studies. et al., 2004). It was firstdescribed by Wight and Arnott (1834) based on two species, M. rubiginosa Wight Working within the current generic framework & Arn. and M. splendens Wight & Arn. The genus (Dunn, 1912) for the Flora of Thailand, we describe comprises approximately 150 tropical species three new species under the broad generic circum- (Schrire, 2005). Recent molecular studies have shown scription of the genus Millettia (sensu Geesink, that the circumscription of Millettia is confused, with 1984). Additionally, we present new synonymies, other larger and smaller genera in the tribe Millettieae lectotypifications and a new status. sensu Geesink (1984) nested within it (Käss & Wink, 1995, 1996; Doyle et al., 1997, 2000; Hu 2000; Hu NEW SPECIES et al., 2000, 2002; Kajita et al., 2001; Wojciechowski et al., 2004). These publications suggest the necessity 1. Millettia phuwuaensis Mattapha & Suddee, for a re-consideration of the generic circumscriptions sp. nov. in this tribe, including Millettia. To date, phylogenetic This species is similar to Millettia penicillata relationships of Millettia and several other genera Gagnep. in having distinct red lines on the outer 1 Department of Biology, Faculty of Science, Udon Thani Rajabhat University, Udon Thani 41000, Thailand. 2 Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK. 3 School of Biological Sciences, University of Reading, Whiteknights, Reading, Berkshire, RG6 6BX, UK. 4 Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation, Chatuchak, Bangkok 10900, Thailand. 5 Department of Biology and Center of Excellence on Biodiversity (BDC), Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. * Corresponding author: [email protected] © 2019 Forest Herbarium 172 THAI FOREST BULLETIN (BOTANY) VOL. 47 NO. 2 surface of the standard, but differs in its fewer leaflets oblong, ca 1 × 0.5 mm. Disk tubular, ca 1 mm long, (5–7 vs 9–17 in M. penicillata), shorter pseudoracemes not lobed. Ovary densely hairy, 7–8 mm long, 1- or or pseudopanicles (up to 10 cm long vs 8–28 cm in 2-ovuled; style 3–4 mm long, hairy at base. Fruits M. penicillata), monadelphous stamens (vs diadelphous elliptic to oblong, woody, dehiscent, 4–5 × 2–2.5 cm. stamens in M. penicillata) and a tubular disk (vs disk Seeds 1 (or 2), orbicular, ca 2 × 2 cm. absent in M. penicillata). Type: Thailand, Bueng Thailand.— NORTH-EASTERN: Bueng Kan Kan Prov., Tham Phun waterfall, ca 300 m alt., [Tham Phun waterfall, 21 Oct. 2015, Mattapha et al. deciduous and bamboo forests, 21 Oct. 2015, 1127 (BK, BKF, K, KKU, L, P, QBG)]. 141 m, 18°1559.2 N 103°54 13.3 E, Mattapha, Suddee & BKF staff 1127 (holotype BKF!; isotypes Distribution.— Only known from the type BK!, K!, KKU!, L!, P!, QBG!). Fig. 1. locality (Fig. 5, closed square). Climber, slender; young branches, inflores- Ecology.— Deciduous and bamboo forests, ca cences and fruits densely hairy with ferruginous 300 m alt. Flowering October–November; fruiting hairs. Leaves imparipinnate, spiral; stipules ovate, December–January. 1–2 × ca 1 mm long, caducous, hairy; petioles 6–9 cm Vernacular.— Phan na rai phu wua (พรรณรายภูวัว). long, densely hairy; rachis 2–6 cm long, shallowly Etymology.— The specific epithet refers to the grooved above, hairy, ultrajugal part absent. Leaflets type locality. 5–7, opposite; stipels setaceous, 2–6 mm long, glabrous, persistent; petiolules 3–5 mm long; lamina Conservation status.— Assessed using GeoCat elliptic, 8–22 × 3–7 cm, apex acute to caudate, base (Bachman et al., 2011), this taxon is Critically cuneate, margin entire, both surfaces sparsely hairy, Endangered (CR), because its estimated Area of 2 moderately hairy along the midrib; lateral veins Occupancy (AOO) is <1 km and its Extent of 2 10–18 pairs, raised below, terminal leaflet equal to Occurrence (EOO) is 4 km . This is insufficient lateral leaflets.Pseudoracemes up to 10 cm long or information to warrant formal designation, as only intermediate forms with pseudopanicles, axillary or a single location is known so far. A further assessment, inserted on old branches. Brachyblasts present, following the gathering of more distribution data, bearing 5–10 flowers; bracts of brachyblasts ovate, should be carried out. ca 1 × 0.5 mm, apex acute, margin hairy, outside Notes.— Millettia phuwuaensis has distinctive glabrous, inside densely hairy with puberulent hairs, red lines and dense puberulent hairs on the outer caducous; bracts of flowers similar to bracts of surface of the standard. The reddish lines look super- brachyblasts but smaller; bracteoles inserted at calyx ficially similar to those of M. penicillata but are base, similar to floral bracts but slightly smaller. thicker and more unevenly scattered (vs parallel in Pedicels ca 4 mm long, puberulent. Calyx cup- M. penicillata). Additionally, Millettia phuwuaensis shaped: tube ca 3 mm long, reddish to dark red; lobes is recognised by its narrowly obovate and larger triangular, minute, apex acute, margin entire, outside standard petal (14–15 × 12–13 mm vs orbicular and puberulent, inside glabrous. Corolla pinkish to pale 8–9 × 9–10 mm in M. penicillata). purple; standard narrowly obovate, 14–15 × 12–13 mm, claw ca 2 mm long, apex retuse, base tapering 2. Millettia pyrrhocarpa Mattapha, Forest & to the claw, with basal callosities, margin entire, Hawkins, sp. nov. outside with scattered reddish lines, striate, puberulent in upper half, inside glabrous; wings more or less This species is similar to Millettia sericea triangular, 9–10 × ca 4 mm, claw 3–4 mm long, base (Vent.) Wight & Arn. ex Hassk., in having ferruginous truncate, apex rounded, margin entire, both sides hairs on the exocarp surface of the fruits, but differs glabrous, sculptured outside and dilated near base; in its caudate leaflet apices (rather than the acute or keel falcate, 8–9 × ca 4 mm, claw ca 5 mm long, apex retuse apices in M. sericea). The lower leaf surface rounded, margin entire, outside puberulent at apex, is densely hairy along the midrib, but otherwise inside glabrous, dilated. Stamens monadelphous, with glabrous (vs densely sericeous throughtout in basal fenestrae, ca 2 mm long, glabrous; staminal M. sericea), the standard petal has basal callosities tube 9–10 mm long; filaments 2–3 mm long; anthers tapering into the claw (vs basal callosities absent in THREE NEW SPECIES, LECTOTYPIFICATIONS AND SYNONYMISATIONS IN MILLETTIA (FABACEAE: PAPILIONOIDEAE) FOR THAILAND (S. MATTAPHA, F. FOREST, J. HAWKINS, S. SUDDEE, N. TETSANA & P. CHANTARANOTHAI) 173 Figure 1. Millettia phuwuaensis: A. Leaves and inflorescence; B. Stipels; C. Inflorescence; D. Standard petals showing inside (left) and outside (right); E. Wing petals; F. Keel petals; G. Stamens; H. Ovary; I. Fruits (drawn from Mattapha et al. 1127). Illustrations by Chadtip Rodtassana. 174 THAI FOREST BULLETIN (BOTANY) VOL. 47 NO. 2 M. sericea), and brachyblasts carry ca 3 flowers (vs densely hairy with ferruginous hairs. Seeds 1–3, 10 or more in M. sericea). Type: Thailand, Nakhon oblong, ca 1.4 × 1 cm. Nayok Prov., Mueang district, Hin Tang subdistrict, Thailand.— CENTRAL: Nakhon Nayok Khao Yai National Park, Nang Rong waterfall, 6 [Mueang, Nang Rong waterfall, Khao Yai National Apr. 2018, ca 100 m alt., 14°19’44.4”N Park, by the stream, 6 Apr. 2018, Mattapha 1139B 101°19’07.0”E, Mattapha 1139B (holotype BKF!; (AAU, BK, BKF, E, K, KKU, L, P, QBG); ibid., isotypes BK!, K!, KKU!, L!, P!, QBG!). Figs. 2 & 28 Oct. 2015, Mattapha 1139A (BKF, KKU); ibid, 4 (A–B). 4 Apr. 1972, Maxwell 72-196 (BK, BKF, L); ibid., Woody climber; young twigs glabrous, lenti- 13 May 1984, Suvatabandhu s.n. (BK SN210695)]. cellate, indumentum of ferruginous hairs scattered Distribution.— Only known from the type throughout. Leaves imparipinnate, usually fasicled locality (Fig. 5, closed triangle). on terminal branches; petioles 5–7 cm long, glabrous; stipules triangular; rachis 8–10 cm long, shallowly Ecology.— Along waterfall, ca