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| Millettia sirindhorniana Mattapha, Thanant., Kaewmuan & Suddee, in Mattapha, Suddee, Tetsana, et al., 2022. photos by Theerawat Thananthaisong. |
Abstract
Two new species of the genus Millettia, M. sirindhorniana and M. tomentosa, are herein described and illustrated. Millettia sirindhorniana shares morphological characteristics with M. extensa and M. fruticosa in being a woody climber with the same leaflet shape and inflorescence type. However, it differs from those species by the presence of stipels and basal callosities, and its shallowly crenate floral disk. Millettia tomentosa is similar to M. extensa and M. suddeei, but differs from the first species by having a brachyblast bearing ca 10 flowers, the standard with basal callosities, presence of a tubular floral disk and oblong to slightly obovate fruits; and it differs from the latter by the absence of stipels, the standard with swollen basal callosities, monadelphous stamens and the tubular floral disc. Descriptions, illustrations, colour plates, vernacular names, etymology, conservation status and key diagnostic characteristics are provided.
Keywords: Khun Kon Waterfall, Leguminosae, Pala-U, Pha Son Kaeo, Suan Phueng
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| Millettia sirindhorniana Mattapha, Thanant., Kaewmuan & Suddee: A. Leaves and inflorescences; B. Standard showing basal callosities on inner surface; C. & D. Wings; E. Keel petals, lateral pockets not shown; F. & G. Stamens showing the basal fenestrae(an opening pore) and side view, respectively; H. Ovary; I. Fruits. A.–H. drawn from Thananthaisong et al. 429; I. drawn from Thananthaisong et al. 135. Illustrations by Orathai Kerdkaew. |
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| Millettia sirindhorniana Mattapha, Thanant., Kaewmuan & Suddee: A. Leaves and inflorescences; B. Leaf; C. Inflorescences; D. Close up of inflorescence; E. Calyx with stamens inside; F. Standard; G. & H. Wing petals; I. Keel petals showing lateral pockets in inner side; J. Stamens showing basal fenestrae; K. Side view of stamens; L. Ovary with 10 shallowly crenate lobes (green line); M. Fruits. All photos by Theerawat Thananthaisong. |
Millettia sirindhorniana Mattapha, Thanant., Kaewmuan & Suddee, sp. nov.
This species resembles Millettia fruticosa (DC.) Benth. ex Baker in having subterminal inflorescences, but differs in having leaves without stipels (present in M. fruticosa), standard petal with basal callosities (vs without basal callosities in M. fruticosa), the base of the standard tapering into the claw (vs abruptly constricted into the claw in M. fruticosa), pseudo-monadelphous stamens (vs truly monadelphous in M. fruticosa), and the presenceof floral disk (vs absent in M. fruticosa). It is also similar to M. extensa (Benth.) Benth. ex Baker but differs in having the terminal leaflet the same size aslateral ones or slightly larger (vs terminal leaflet muchlarger than lateral ones in M. extensa), absence of stipels (vs present in M. extensa), each brachyblasts having 3–5 flowers (vs 1–3 flowers in M. extensa), purple flowers, rarely white (vs pinkish to creamy white flowers in M. extensa) and presence of floral disk (vs no floral disk in M. extensa).
Etymology.— The specific epithet is chosen to honour Her Royal Highness Princess Maha Chakri Sirindhorn of Thailand for her dedication to science and encouragement of conservation in Thailand.
Vernacular.— Muang Ratcha Sirin (ม่วงราชสิริน)
(name given by H.R.H. Princess Maha Chakri Sirindhorn).
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| Millettia tomentosa Mattapha & Tetsana: A. Leaves and inflorescences; B. Part of inflorescence with close up of flowers; C. Young floral buds; D. Mature flower; E. & F. Standard petals; G. Wing petals; H. Keel petals showing abaxial surface; I. Calyx with stamens inside; J. Ovary; K. Fruit; L. Seed. All photos by Sawai Mattapha. |
Millettia tomentosa Mattapha & Tetsana sp. nov.
This species is most similar to Millettia suddeei Mattapha & Tetsana, being a liana with up to 9 leaflets,the terminal leaflet being mostly obovate and in having pseudoracemes but it differs in the absence of stipels (present in M. suddeei), the standard with swollen basal callosities (absent in M. suddeei), monadelphous stamens and presence of the tubular floral disk. It is also similar to M. extensa in having a brown tomentose indumentum on young branches, the colour and length of standard, monadelphous stamens and a tomentose ovary, but differs in having 5–9 leaflets (vs 7–11 leaflets in M. extensa), absence of stipels (vs present in M. extensa), having 4–5 pairs of secondary veins (vs 8–12 pairs in M. extensa), each brachyblast bearing ca 10 flowers (vs 1–3 flowersin M. extensa), the standard with basal callosities on the inner side in the middle of the claw and presence of the tubular floral disk.
Etymology.— The specific epithet refers to the densely tomentose ovary and fruits.
Vernacular.— Son kaeo (ซ่อนแก้ว) (proposed here).
Sawai Mattapha, Somran Suddee, Naiyana Tetsana, Theerawat Thananthaisong and Anusara Kaewmuan. 2022. Millettia sirindhorniana and M. tomentosa, Two New Species of Millettia (Fabaceae: Millettieae) for Thailand. Thai Forest Bulletin (Botany). 50(2), 89–99. DOI: 10.20531/tfb.2022.50.2.09
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
