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| Begonia tanauanensis Tandang, Bucay & K.F.Chung, in Bucay, Tandang, Rubite, Jallores et Chung, 2024. |
Abstract
Begonia tanauanensis is a newly described endemic species in B. sect. Baryandra from Tanauan City, Batangas, southern Luzon, Philippines. Morphological data shows this species resembles B. chingipengii, a species from eastern Luzon as both species have light pink flowers, fleshy green lamina, and boat-shaped bracts. However, B. tanauanensis does not have the prominent white midrib and veins in the adaxial leaf surface, ciliate hairs on leaf margin, strongly keeled stipules and tomentose hairs on the abaxial leaf surface and petioles of B. chingipengii. The plants were observed to have a restricted and severely fragmented distribution. Unfortunately, these observed populations are also affected by human activities and threat of volcanic activity of the nearby Taal Volcano. Because of these threats, we provisionally assess the species as “Critically Endangered” (CR) following the IUCN Red List Categories and Criteria.
Key words: archipelago, Critically Endangered, Taal Volcano, Tanauan City, Eudicots
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| Begonia tanauanensis Tandang, Bucay & K.F.Chung. A. Habit; B. Leaf and petiole; C–D. Young leaf, adaxial and abaxial views; E. Leaves showing the abaxial vestiture; F. Large mature leaf. Photographs by Danilo N. Tandang and Mark Angelo C. Bucay. |
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| Begonia tanauanensis Tandang, Bucay & K.F.Chung. A. Rhizome; B. Abaxial view of the partly-keeled stipules; C–D. Bracts from the first lower node and uppermost part of inflorescence; E–F. Habit, G. Inflorescence; H–I. Staminate flower, face view and side view; J. Androecium side view; K–L. Pistillate flower, face and side views; M. Stigma; N–O–P. Fresh capsule side, face, and cross section view respectively. Photographs by Danilo N. Tandang. |
Begonia tanauanensis Tandang, Bucay & K.F.Chung, sp. nov.
§ Baryandra
Diagnosis:—Among the tallest of the currently described Philippine Baryandra species in its section, B. tanauanensis has the closest vegetative and reproductive structures to B. chingipengii from Gabaldon, Nueva Ecija in Eastern Luzon by having broad ovate leaves, boat-shaped bracts and light pink flowers. However, B. tananuanensis’s stipules have no keels, or sometimes partly keeled (versus strongly keeled in B. chingipengii), solid green adaxial leaf surface (versus dark green with prominently white midrib and veins of B. chingipengii), setose abaxial leaf surface and petioles (versus tomentose), and glabrous leaf margins (versus ciliated leaf margins). Other key differences are summarized in Table 1.
Etymology:—The specific epithet “tanauanensis” is named after the place of its origin, Tanauan City, Batangas in southern Luzon, Philippines.
Mark Angelo C. Bucay, Danilo N. Tandang, Rosario R. Rubite, Edison Jallores Jr. and Kuo-Fang Chung. 2024. A New Begonia Species (sect. Baryandra, Begoniaceae) from Batangas Province, Luzon Island, Philippines. Phytotaxa. 641(4); 277-285. DOI: 10.11646/phytotaxa.641.4.4