Open AccessA taxonomic revision of taxa in Styrax series Cyrta (Styracaceae) with valvate corollas
Author(s) -
Gary Li,
Peter W. Fritsch
Publication year - 2018
Publication title -
journal of the botanical research institute of texas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.316
H-Index - 22
eISSN - 2644-1608
pISSN - 1934-5259
DOI - 10.17348/jbrit.v12.i2.962
Subject(s) - taxon , biology , botany , taxonomy (biology) , genus , zoology
Several taxonomic treatments of Styrax (Styracaceae) exist in regional floras of Asia, but the Asian species of the genus have not been comprehensively revised since 1907. A treatment of the Asian taxa of S. series Cyrta with imbricate floral aestivation was accomplished in 2003. To complete the taxonomic revision of S. series Cyrta, we conducted a taxonomic revision of the species of the series with valvate aestivation of the corolla lobes. Our revision comprises 11 species with a combined distribution from eastern India through southern China and Malesia, Melanesia, and Micronesia, although the group is absent from the Philippines. We resurrected S. bracteolatus, S. rubifolius, and S. warburgii as species to be recognized, and we corrected the misapplication of S. finlaysonianus, previously used for a species in S. series Benzoin. Styrax finlaysonianus and S. warburgii are segregated from the broader concept of S. agrestis recognized in prior treatments. The circumscriptions of the heretofore poorly delimited species S. confusus, S. faberi, and S. fortunei are clarified and their possible introgressants discussed. We observed unique combinations of characters in some problematic specimens whose taxonomic status remains unresolved because only single specimens with either flowers or fruits were available; at least some of these may represent undescribed species. Lectotypes are designated for Cyrta agrestis, S. argyi, S. bracteolatus, S. calvescens, S. casearifolius, S. confusus var. microphyllus, S. dasyanthus, S. dasyanthus var. cinerascens, S. faberi, S. finlaysonianus, S. formosanus, S. fortunei, S. fukienensis, S. henryi, S. henryi var. microcalyx, S. iopilinus, S. philadelphoides, S. rostratus, S. rubifolius, S. serrulatus var. agrestis, and S. virgatus. A neotype is designated for S. warburgii. Keys, descriptions, distribution maps, and conservation assessments are provided for all species. Styrax agrestis, S. bracteolatus, and S. rubifolius are rare endemics of conservation concern, with highly restricted distributions.