Morphological, molecular, and biogeographic evidence for specific recognition of Euthamia hirtipes and Euthamia scabra (Asteraceae, Astereae)

The number and identity of species in the North American genus Euthamia (Asteraceae, Astereae) have varied considerably among taxonomic treatments. Euthamia graminifolia (L.) Nutt. is often treated to broadly include plants from the northern and eastern United States and Canada, including the Atlantic and Gulf Coasts. Broad-leaved, largely glabrous plants from New Jersey to the Florida Panhandle have been inconsistently treated as E. graminifolia, E. graminifolia var. hirtipes (Fernald) C.E.S. Taylor & R.J. Taylor E. hirtipes (Fernald) Sieren , or a hybrid between E graminifolia and E. caroliniana (L.) Greene ex Porter & Britton . Similarly, plants from the Florida Panhandle to eastern Louisiana have been incorporated into either E. graminifolia or E. graminifolia var. hirtipes, with only Greene in 1902 recognizing southern plants as a distinct species, E. scabra Greene . To determine the identity and proper rank of these entities, morphological and p...北美一枝黄花属（Euthamia，菊科Asteraceae，紫菀族Astereae）的物种数量与分类界定，在不同的分类学处理中差异显著。禾叶一枝黄花（Euthamia graminifolia (L.) Nutt.）通常被广义地处理为包含美国东北部、东部以及加拿大的类群，其分布范围涵盖大西洋沿岸与墨西哥湾沿岸区域。从新泽西州至佛罗里达狭长地带的宽叶、近无毛类群，其分类处理始终缺乏统一标准：时而被归为E. graminifolia，时而被处理为E. graminifolia var. hirtipes (Fernald) C.E.S. Taylor & R.J. Taylor、E. hirtipes (Fernald) Sieren，亦或是被认定为E. graminifolia与E. caroliniana (L.) Greene ex Porter & Britton的杂交类群。同样，从佛罗里达狭长地带至路易斯安那州东部的类群，要么被归入E. graminifolia，要么被归为E. graminifolia var. hirtipes；仅Greene在1902年将南部类群认定为独立物种E. scabra Greene。为明确这些类群的分类地位与正确分类等级，本研究开展了形态学与……