A taxonomic revision of Philadelphus (Hydrangeaceae) in South Korea

Abstract

The genus Philadelphus (Hydrangeaceae) in South Korea is critically revised based on macro- and micro-morphological characteristics from over 1,000 herbarium specimens, and fresh material from wild populations. Findings show that: (1) The presence/absence and the density of the hairs on the disk, pistil, calyx, leaves, and petiole and the degree of division of the style are insufficient characters for recognizing species in Philadelphus. (2) Philadelphus koreanus, P. robustus, P. scaber, and P. seoulensis were confirmed to be synonyms of P. tenuifolius. (3) Philadelphus lasiogynus is newly synonymized into P. tenuifolius based on the type material. (4) Philadelphus pekinensis has been excluded from the Korean flora because of prior misidentifications of herbarium specimens, whose identity is very sparsely pubescent P. tenuifolius. It is therefore confirmed that only P. tenuifolius has been recorded in South Korea. Detailed morphological descriptions, photographs, illustrations, distribution maps, and information on the herbarium materials of P. tenuifolius in South Korea are provided.

Keywords

• Hydrangeaceae
• Morphology
• Philadelphus
• South Korea
• Taxonomic revision