Two new species of Aphyllon from northeastern Mexico: Sequence alignments and phylogenetic trees

Plants originally identified as Aphyllon ludovicianum that occur near Monterrey, Nuevo Leon, and Cuatro Ciénegas Bolson, Coahuila, Mexico, were found to not align with the protologue of that species, the close relative A. multiflorum, or any other species of Aphyllon. Following a detailed study of floral morphology, geographic range, host species, and phylogenetic position using dry herbarium specimens, field study and georeferenced color photographs, we propose the new binomials Aphyllon spectabile for the plants from Nuevo Leon and Aphyllon gypsophilum for the plants from Coahuila, Mexico. This increases the taxonomic diversity of Aphyllon to 27 species plus ten additional subspecies. Gymnosperma glutinosum and two species of Xanthisma were reported for the first time as a host species for the genus Aphyllon. We also provide an updated key to Aphyllon in Mexico.Â

最初被鉴定为路德维希无叶列当（Aphyllon ludovicianum）的植株，分布于墨西哥新莱昂州蒙特雷附近以及科阿韦拉州的夸特罗西内加斯盆地（Cuatro Ciénegas Bolson），经研究发现其既不符合该物种的原始发表描述，也与近缘种多花无叶列当（A. multiflorum）及其他任何无叶列当属（Aphyllon）物种均不相符。研究团队通过干燥腊叶标本、野外考察及带地理坐标的彩色照片，对其花部形态、地理分布、宿主物种及系统发育位置开展了详细研究，据此将分布于新莱昂州的类群命名为新种壮丽无叶列当（Aphyllon spectabile），将分布于墨西哥科阿韦拉州的类群命名为新种石膏生无叶列当（Aphyllon gypsophilum）。此举使无叶列当属（Aphyllon）的分类学多样性增至27个物种及10个亚种。本研究首次报道了胶状裸子菊（Gymnosperma glutinosum）以及两种黄晶菊属（Xanthisma）物种作为无叶列当属的宿主植物。同时，本研究还提供了墨西哥地区无叶列当属物种的最新检索表。