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| Millettia suddeei Mattapha & Tetsana
in Mattapha, Forest, Hawkins, et al., 2019.
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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 of Millettia are proposed and Millettia tecta is raised to species status.
KEYWORDS: Generic circumscription, Leguminosae, Millettieae, taxonomy
Millettia phuwuaensis Mattapha & Suddee, sp. nov.
This species is similar to Millettia penicillata Gagnep. in having distinct red lines on the outer surface of the standard, but differs in its fewer leaflets (5–7 vs 9–17 in M. penicillata), shorter pseudoracemesor pseudopanicles (up to 10 cm long vs 8–28 cm in M. penicillata), monadelphous stamens (vs diadelphous stamens in M. penicillata) and a tubular disk (vs disk absent in M. penicillata).
Vernacular.— Phan na rai phu wua (พรรณรายภูวัว, หางไหลภูวัว).
Etymology.— The specific epithet refers to the type locality.
Notes.— Millettia phuwuaensis has distinctive red lines and dense puberulent hairs on the outer surface of the standard. The reddish lines look super-ficially similar to those of M. penicillata but are thicker and more unevenly scattered (vs parallel in M. penicillata). Additionally, Millettia phuwuaensisis recognised by its narrowly obovate and larger standard petal (14–15 × 12–13 mm vs orbicular and 8–9 × 9–10 mm in M. penicillata).
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| Figure 4. A–B: Millettia pyrrhocarpa: A. Inflorescence; B. Fruit. C–E: Millettia suddeei: C. Leaves and inflorescence; D. Part of the inflorescence; E. Papilionaceous flower (Right) and stamens (Left).
Photos by Sawai Mattapha (A–B) & Naiyana Tetsana (C–E).
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Millettia pyrrhocarpa Mattapha, Forest & Hawkins, sp. nov.
This species is similar to Millettia sericea (Vent.) Wight & Arn. ex Hassk., in having ferruginous hairs on the exocarp surface of the fruits, but differs in its caudate leaflet apices (rather than the acute or retuse apices in M. sericea). The lower leaf surface is densely hairy along the midrib, but otherwise glabrous (vs densely sericeous throughtout in M. sericea), the standard petal has basal callosities tapering into the claw (vs basal callosities absent in M. sericea), and brachyblasts carry ca 3 flowers (vs 10 or more in M. sericea).
Vernacular.— Nang rong (นางรอง).
Etymology.— The specific epithet refers to the densely ferruginous hairy fruits.
Notes.— Millettia pyrrhocarpa was collected in the same locality by different collectors, but has remained unrecognised as a new species. We found it amongst unidentified collections with other unnamedMillettia specimens, therefore, only when we had identified flowering and fruiting material could we confirm that it was a new species based on the standard having basal callosities tapering into the claw, presenceof ca 3 flowers on the brachyblasts and the fruits covered with densely ferruginous hairs. Because of the ferruginous indumentum on the fruits, the species was compared with the most similar species, M. sericea. It differs from M. sericea in its smaller and thinner leaflets lacking sericeous hairs on the lower surface, and smaller standard petals (8–9 × 8–9 mm vs 10–13 × 10–12 mm in M. sericea), lacking sericeous hairs on their outer surface (vs densely sericeous in M. sericea).
This species is similar to Millettia sericea (Vent.) Wight & Arn. ex Hassk., in having ferruginous hairs on the exocarp surface of the fruits, but differs in its caudate leaflet apices (rather than the acute or retuse apices in M. sericea). The lower leaf surface is densely hairy along the midrib, but otherwise glabrous (vs densely sericeous throughtout in M. sericea), the standard petal has basal callosities tapering into the claw (vs basal callosities absent in M. sericea), and brachyblasts carry ca 3 flowers (vs 10 or more in M. sericea).
Vernacular.— Nang rong (นางรอง).
Etymology.— The specific epithet refers to the densely ferruginous hairy fruits.
Notes.— Millettia pyrrhocarpa was collected in the same locality by different collectors, but has remained unrecognised as a new species. We found it amongst unidentified collections with other unnamedMillettia specimens, therefore, only when we had identified flowering and fruiting material could we confirm that it was a new species based on the standard having basal callosities tapering into the claw, presenceof ca 3 flowers on the brachyblasts and the fruits covered with densely ferruginous hairs. Because of the ferruginous indumentum on the fruits, the species was compared with the most similar species, M. sericea. It differs from M. sericea in its smaller and thinner leaflets lacking sericeous hairs on the lower surface, and smaller standard petals (8–9 × 8–9 mm vs 10–13 × 10–12 mm in M. sericea), lacking sericeous hairs on their outer surface (vs densely sericeous in M. sericea).
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| Figure 3. Millettia suddeei: A. Leaves & Inflorescence; B. Component of the flowers, composed of standard (upper), wings (lateral) and keel petals (lower); C. Stamens (drawn from Suddee et al. 5206). Illustrations by Orathai Kerdkaew. |
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| Millettia suddeei: C. Leaves and inflorescence; D. Part of the inflorescence; E. Papilionaceous flower (Right) and stamens (Left).
Photos by Naiyana Tetsana
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This species resembles Millettia puerarioides Prain, but differs in having stipels (stipels absent in M. puerarioides), sparsely pubescent hairs on the lower surface of the leaflets (vs densely silky hairs in M. puerarioides), and diadelphous stamens (vs monadelphous in M. puerarioides). It is also characterized by having 7–9 leaflets (vs 5–7 in M. puerarioides), and a standard petal with pubescent hairs on the outer surface (vs densely silky hairs in M. puerarioides).
Vernacular.— Phi lai somran (พิไลสมราน, หางไหลทุ่งใหญ่).
Etymology.— The epithet refers to Dr. Somran Suddee, who first collected the species.
Sawai Mattapha, Felix Forest, Julie A. Hawkins, Somran Suddee, Naiyana Tetsana and Pranom Chantaranothai. 2019. Three New Species, Lectotypifications and Synonymisations in Millettia (Fabaceae: Faboideae) for Thailand. THAI FOREST BULL., BOT. 47(2); 171–183. DOI: 10.20531/tfb.2019.47.2.07
