Wednesday, February 3, 2021

[Botany • 2021] Eriobotrya shanense (Rosaceae) • A New Broad-leaved Species of Loquat from eastern Myanmar and Its Phylogenetic Affinity in the Genus Eriobotrya


Eriobotrya shanense D.H. Kang, H.G. Ong & Y.D. Kim

in Kang, Ong, Lee, ... et Kim, 2021. 

Abstract
Eriobotrya shanense, a new species from the karst region of Shan State, eastern Myanmar, is described and illustrated. This evergreen tree is similar to the autumn and winter-flowering, large-leaved species E. malipoensis and E. japonica by having tomentose hairs on the abaxial leaf surface, but can be distinguished by its obovate, widely obelliptic or oval blade shape, leaf length-width ratio of 2:1 (vs. 3:1), and rounded or obtuse apex (vs. acute). The species also resembles less-known, undercollected Myanmar broad-leaved species E. wardii and E. platyphylla in leaf shape and length-width ratio, but can be easily differentiated by the presence of tomentose hairs on the leaves, and inflorescence. Phylogenetic analysis based on nrDNA ITS region supported its close affinity with E. malipoensis and E. japonica. Molecular data also generally grouped the 17 congeneric taxa accessions in congruence to their leaf morphology, with the entire Eriobotrya clade strongly supported to be monophyletic and separate from Rhaphiolepis.

Keywords: ITS, limestone karst, Panlaung Pyadalin Cave Wildlife Sanctuary, phylogeny, Shan State

Eriobotrya shanense D.H. Kang, H.G. Ong & Y.D. Kim
A. Flowering branch B. Leaf blade C–D. Stipules E. Bract F–G. Flower abaxial and adaxial view H–I. Petals J. Flower longitudinal section showing the androecium and gynoecium K. Stamen L. Styles and exposed ovary M. Ovary cross section N. Fruiting branch O–P. Fruit cross and longitudinal section. A–M. from Kim et al. MM-6026 (holotype HHU). Illustration by Ye-Seul Jang.

Eriobotrya shanense D.H. Kang, H.G. Ong & Y.D. Kim.
A. Habitat B. Stipule and petiole C. Inflorescence D. Flower E. Petals (base not clawed) F. Fruiting branch.
 
Eriobotrya shanense D.H. Kang, H.G. Ong & Y.D. Kim, sp. nov. 

Type:— MYANMAR. Southern Shan State, Ywangan Township, N21° 14’ ...” E96° 25’ ...”, elev. 1,422 m, 01 Jan. 2017, Kim et al. MM-6026 (holotype HHU barcode 880000016009; isotypes HHU barcode 880000016016, KB barcode 880000016023, RAF barcode 880000016030). 

Diagnosis:— Leaf morphology of Eriobotrya shanense is similar to that of E. malipoensis and E. japonica by having tomentose hairs on the abaxial surface of its blade but can be differentiated by its obovate, widely obelliptic or oval blade shape, its length-width ratio of 2:1 (vs. 3:1), and rounded or obtuse apex (vs. acute). The species also resembles less-known, undercollected Myanmar broad-leaved species E. wardii and E. platyphylla in leaf shape and length-width ratio, but can be easily differentiated by the presence of tomentose hairs on the leaves and inflorescence.
 See Table 1 for a detailed comparison. 

Etymology:— Eriobotrya shanense is named after its type locality, Shan State in eastern Myanmar.

Distribution and habitat:— Eriobotrya shanense is known to be narrowly distributed in its type locality, Ywangan Township in southern Shan State. So far, two populations have been found, one consisting of not less than 10 fullgrown trees, and the other of ca. 20 mature and juvenile individuals. The tree grows on slopes of irregularly rocky limestone karst hills, along with Firmiana kerri (Craib) Kostermans (1961: 389), Sterculia villosa Roxburgh (1832: 153, 154), Wightia speciosissima (D. Don) Merrill (1938: 67), Bauhinia variegata Linnaeus (1753: 375), Ceratostigma asperrimum Stapf ex Prain (1906: 6, 7), and Trichodesma calycosum Collett & Hemsley (1890: 92, 93).


Dae-Hyun Kang, Homervergel G. Ong, Jung-Hoon Lee, Eui-Kwon Jung, Naing-Oo Kyaw, Qiang Fan and Young-Dong Kim. 2021. A New Broad-leaved Species of Loquat from eastern Myanmar and Its Phylogenetic Affinity in the Genus Eriobotrya (Rosaceae).  Phytotaxa. 482(3); 279–290. DOI:  10.11646/phytotaxa.482.3.6