Friday, October 13, 2017

[Botany • 2017] Begonia fulgurata | ดาดดารารัศมี • A New Species (sect. Diploclinium, Begoniaceae) from Chiang Mai, northern Thailand

Begonia fulgurata C.-I Peng, C.W.Lin & Phutthai

ดาดดารารัศมี  ||  DOI:  10.3767/blumea.2017.62.03.01

Begonia fulgurata, a new species from northern Thailand, is here described and illustrated. Begonia fulgurata resembles B. integrifolia, a widespread species in Southeast Asia, in having tubers, erect stem with hairy leaves and a periodically dormant habit. However, the new species is sharply distinct in its lamina densely hirsute (vs sparsely puberulous) and with maroon patches and silvery white veins (vs uniformly green or with white spots); inflorescence densely clothed with glandular hairs (vs glabrous or puberulous); staminate flowers with 2, rarely 3 (vs 4) tepals; staminate and pistillate tepals glandular hairy (vs glabrous). As a deciduous species with basal tubers, together with an erect stem, ovate to broadly ovate leaves, 3-locular ovary, it may be mistaken as a dwarf plant of B. grandis, one of the most widely distributed species in China and the type species of sect. Diploclinium. However, B. fulgurata differs in its leaf upper side with fine silvery (vs green) veins; inflorescence densely glandular hairy (vs glabrous), staminate tepals 2 or rarely 3 (vs 4) and pistillate tepals 5 (vs 3), and ovary glandular hairy (vs glabrous).

Keywords: Chiang Mai; endemic; new species; taxonomy

Currently 54 species of Begonia are recognized in Thailand (Phutthai & Hughes 2016). Many are tuberous and periodically dormant during the dry season, such as some members in sect. DiplociniumParvibegoniaReichenheimiaHeeringia and Monophyllon. All of these species have axile placentae and many were discovered recently, e.g., Doorenbos et al. (1998), Phutthai & Sridith (2010), Phutthai et al. (2014), Phutthai & Hughes (2016). Here we report the discovery of a handsome new species, B. fulgurata, from northern Thailand with partial parietal placentation, which resemble some Begonia sect. Coelocentrum, a relatively large group now of over 70 species (Chung et al. 2014, Peng et al. 2014, 2015a, b) occurring on karst limestone in southern China and northern Vietnam. Members of sect. Coelocentrum are evergreen, stemless rhizomatous, and produce axillary inflorescences and unequally winged fruits. The new species, however, does not fit in sect. Coelocentrum because of its tuberous habit, periodically dormant and erect stems and apical inflorescence and subequal wings. Its overall appearance appears to be allied to sect. Diploclinium. We provide a detailed morphological description, a line drawing and a colour plate to aid in identification of this new species.

Fig. 2 Begonia fulgurata C.-I Peng, C.W.Lin & Phutthai.
 a–b. Habit; c. staminate flower; d. pistillate flower; e. sterile plants with tubers on petiole and at base; f. portion of leaf; g. inflorescence; h. staminate flower and an immature capsule; i. cross section of the middle part of an ovary. 
— Scale bars: c–d = 5 mm; e = 2 cm; f–h = 1 cm; i = 3 mm.
 — Photos: a: Wei-Min Lin; b: Advance Thailand Geographic; c–i: Ching-I Peng.

Begonia fulgurata C.-I Peng, C.W. Lin & Phutthai, sp. nov.

 Type. Thailand, Chiang Mai Province, Doi Lohn (Lahn), west side, ..., Huay Gayo Subdistrict, Mae Awn District. Sterile specimen collected on 23 Oct. 2005, ....Type specimens pressed from plants brought back for cultivation in the experimental greenhouse of Academia Sinica, 26 Aug. 2008 (holo HAST; iso BKF).

Etymology. The specific epithet fulgurata is derived from the fine, silvery-white venation on the leaf upper surface, which resembles lightning.

 C.-I Peng, C.-W. Lin and T. Phutthai. 2017. Begonia fulgurata (sect. Diploclinium, Begoniaceae), A New Species from northern Thailand. Blumea. 62; 163 –167. DOI:  10.3767/blumea.2017.62.03.01

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  1. Please adjust your background colour and font colour. Some portion of the blog becomes unreadable. Thank you !