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| Miliusa chantaburiana Damthongdee & Chaowasku
in Damthongdee & Chaowasku, 2018.
ระฆังจันท์ || DOI: 10.3372/wi.48.48208
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Abstract
Miliusa chantaburiana Damthongdee & Chaowasku, a new species of Annonaceae from SE Thailand, is described and illustrated. It belongs to a clade with campanulate flowers and inner petals that are generally tightly appressed from the base to more or less the midpoint at anthesis. The new species is remarkable in possessing a strongly recurved apex of the inner petals at anthesis and can be principally differentiated from its morphologically closest species, M. pumila Chaowasku and M. filipes Ridl., both from Peninsular Thailand, by the higher number of stamens and carpels per flower and horseshoe-shaped stigmas. Miliusa chantaburiana is also unique in having a 6-base-pair insertion in the plastid matK sequence. A revised key to species in the campanulate-flowered clade in Thailand is given.
Keywords: Annonaceae, Chantaburi, matK, Miliusa, Miliuseae, new species, systematics, taxonomy, Thailand
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| Fig. 2. Leaf and flower of Miliusa chantaburiana – A: abaxial (lower) leaf surface; B: adaxial (upper) leaf surface; C: flower, apical view showing stamens, carpels, inner petal discolouration and translucent window-like structures; D: flower, oblique view showing strongly recurved apical part of inner petals.
– Scale bars: A = 2 cm; B = 10 cm; E = 1 mm; F = 0.5 mm.
– A, B from cultivated material; C–F from Nakorn-Thiemchan NTC 29 (CMUB – spirit material).
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Miliusa chantaburiana Damthongdee & Chaowasku, sp. nov.
Holotype: Thailand, cultivated in Bangkok [sapling originally from Khiri Than Dam, Chantaburi Province], 7 Feb 2015 [in flower], Nakorn-Thiemchan NTC 29 (CMUB!; isotypes: B!, P!).
Diagnosis — Miliusa chantaburiana is morphologically close to M. pumila and M. filipes, both occurring in Peninsular Thailand (Chaowasku 2014). The new species differs mainly from M. pumila by having generally larger leaf blades ([9.2–] 12.2–18[–19.5] x [2.8–]3.3–6 cm vs 5.4–10.5 x 2–4.1 cm), generally longer pedicels ([11–] 14–22[–30] mm vs 5–11 mm), more stamens per flower (48–50 vs 38–39), and many more carpels per flower (49–71 vs 12–13). The new species primarily differs from M. filipes by possessing considerably more stamens (48–50 vs c. 22) and carpels (49–71 vs c. 16) per flower. In addition, M. chantaburiana exhibits horseshoe-shaped stigmas, whereas they are subglobose to ellipsoid(-obovoid) in M. pumila (Chaowasku 2014) and capitate in M. filipes.
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| Fig. 1. Holotype of Miliusa chantaburiana Damthongdee & Chaowasku, Nakorn-Thiemchan NTC 29 (CMUB). |
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Fig. 2. Leaf and flower of Miliusa chantaburiana –
A: abaxial (lower) leaf surface; B: adaxial (upper) leaf surface; C: flower, apical view showing stamens, carpels, inner petal discolouration and translucent window-like structures; D: flower, oblique view showing strongly recurved apical part of inner petals; E: stamens attached to torus; F: carpel.
– Scale bars: A = 2 cm; B = 10 cm; E = 1 mm; F = 0.5 mm.
– A, B from cultivated material; C–F from Nakorn-Thiemchan NTC 29 (CMUB – spirit material).
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| Fig. 3. Flower, fruit and seed of Miliusa chantaburiana – A: abaxial surface (outside) of an inner petal; B: adaxial surface (inside) of an inner petal; C: flower, basal view showing sepals and outer petals; D: fruit with five monocarps; E: flower with one inner petal pulled apart from others showing a mass of stamens and carpels; F: seed.
– Scale bars: A, B, E, F = 5 mm; C = 3 mm; D = 2 cm.
– A, B, E from Chaowasku 170 (CMUB – spirit material); C from Nakorn-Thiemchan NTC 29 (CMUB – spirit material); D from Chaowasku 171 (CMUB – spirit material); F from Nakorn-Thiemchan NTC 28 (CMUB – spirit material).
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Distribution and ecology (at original locality) — Chantaburi Province, SE Thailand (Fig. 4); occurring in partially disturbed evergreen forests around a constructed dam; at an elevation of c. 205 m.
Conservation status — This species is known only from a very restricted area, i.e. around Khiri Than Dam of Chantaburi Province, SE Thailand (Fig. 4). Fewer than 10 individuals were observed in the area, some of which occur adjacent to the reservoir and could be submerged in the near future, and it is believed that many more individuals have been submerged during dam construction. Further, this species has never been reported to occur in nearby areas (e.g. Khao Khitchakut National Park, Khao Soidao Wildlife Sanctuary, Namtok Phliu National Park and Namtok Khlongkaew National Park) and no specimens have been collected prior to the present study. Based on this information, Miliusa chantaburiana is undoubtedly a rare species; however, we believe that more exploratory data, especially from Cambodia (which is merely c. 20 km away from the dam), are required prior to the assessment of the conservation status of this species. Therefore, it is considered here as Data Deficient (DD) (IUCN 2012).
Etymology — The epithet refers to Chantaburi, the SE Thai province where this species is endemic.
Anissara Damthongdee and Tanawat Chaowasku. 2018. Miliusa chantaburiana (Annonaceae), A New Species from SE Thailand. Willdenowia. 48(2); 293-301. DOI: 10.3372/wi.48.48208
