Wednesday, January 24, 2018

[Botany • 2018] A Revision of Begonia L. (Begoniaceae, Cucurbitales) from Northeast India with Description of A New Species, Begonia koelzii

Begonia acetosella Craib.; Begonia annulata K.Koch.; Begonia dioica Buch.-Ham. ex D.Don.   
  Begonia beddomei Hook.f. by M. Smith (Hooker 1884); Begonia cathcartii Hook.f. by W.H. Fitch (Hooker 1855); Begonia pedunculosa Wall. by Vishnupersaud (Wallich 1830).

in Camfield & Hughes, 2018. 
  DOI:  10.5852/ejt.2018.396 


Following a taxonomic revision of Begonia L. (Begoniaceae, Cucurbitales) from Northeast India based on 332 herbarium specimens, 38 species are confirmed to occur in the region, of which ten are endemic. One new species is described, Begonia koelzii R.Camfield sp. nov., in B. sect. Platycentrum (Klotzsch) A.DC. One species is reduced into synonymy; B. barbata Wall. is now a synonym of B. thomsonii A.DC. Three species, B. difformis (Irmsch.) W.C.Leong, C.I Peng & K.F.ChungB. labordei H.Lév. and B. handelii Irmsch., are reported new for India, and B. lushaiensis C.E.C.Fisch. is reinstated as an accepted species, having previously been synonymised under B. modestiflora Kurz. A key to the species in the region and preliminary conservation assessments are presented.

Keywords: Begonia; taxonomy; revision; Northeast India

Fig. 7. Begonia acetosella Craib. A. Plant habit. B–C. Leaf variation. D. Female bud. E. Female flower. F. Reverse of flower. G. Styles. Photographs by Rebecca Camfield of a plant in cultivation at the Royal Botanic Garden Edinburgh (accession 19980065).  
Fig. 11. Begonia annulata K.Koch. A–B. Leaf. C. Male flower. D–E. Fruit. Photographs courtesy of Darrin Norton of a plant in cultivation in a private collection.
Fig. 23. Photograph showing habit and female flowers of Begonia dioica Buch.-Ham. ex D.Don. Photograph courtesy of Sangeeta Rajbhandary of a plant in Nepal.

Fig. 13. Illustration of Begonia beddomei Hook.f. by M. Smith (Hooker 1884). 1. Stamen. 2. Styles. 3. Fruit cross-section. Image from the Biodiversity Heritage Library, digitized by the Peter H. Raven Library  
Fig. 20. Illustration of Begonia cathcartii Hook.f. by W.H. Fitch (Hooker 1855). 1–3. Stamen, front, back and side view. 4. Pollen. 5. Immature fruit. 6. Cross-section of fruit showing ovary placentation. Image from the Biodiversity Heritage Library, digitized by the Peter H. Raven Library
Fig. 47. Illustration of Begonia pedunculosa Wall. by Vishnupersaud (Wallich 1830). 1. Male flower, front view. 2. Male flower, reverse view. 3. Female flower, front view. 4. Female flower, reverse view. Image from the Biodiversity Heritage Library, digitized by the Peter H. Raven Library

Fig. 34. Begonia koelzii R.Camfield sp. nov. A. Plant habit. B. Leaf. C. Bulbil. D. Young female flowers. E. Fruit. Photographs courtesy of Nick Macer, of a plant in Manipur. 

Begonia koelzii R.Camfield sp. nov. [sect. Platycentrum]
 Diagnosis:  Similar to B. macrotoma Irmsch. (1951: 41) in having lacerate leaves, but differs in having a larger lamina (20–40 cm long, not 12–15 cm) and female flowers with 4–6 (not 3) tepals.

Etymology: The epithet honours Walter N. Koelz (1895–1989), the American zoologist who collected the type.

Distribution and phenology: Endemic to the Arakan Mountain Range, usually found growing on cliff faces; 1000–2100 m.

Conservation status Data Deficient: The full distribution of B. koelzii in the Arakan mountains is unknown

Rebecca Camfield and Mark Hughes. 2018.   A Revision and One New Species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India.  European Journal of Taxonomy. 396;  1–116. DOI:  10.5852/ejt.2018.396