基于分子与形态证据的桃色无心菜(石竹科)分类地位探讨

Taxonomic Investigation of Arenaria melandryoides(Caryophyllaceae):Insights from Molecular and Morphological Data

广义无心菜属(Arenaria L.s.l.)是石竹科(Caryophyllaceae)中分类较为困难的大属之一,基于分子系统学研究结果该属目前已被拆分为多属。基于形态学证据,桃色无心菜(Arenaria melandryoides Edgew.)被置于无心菜属齿瓣亚属[subg.Odontostemma(G.Don)Williams]、齿瓣无心菜属(Odontostemma Benth.ex G.Don)或独缀草属[Shivparvatia(Edgew.)Pusalkar&D.K.Singh]之中,但都缺少分子系统学证据的支持。基于ITS序列重建了繁缕族(Alsineae)系统发育关系,结果表明:目前所界定的齿瓣无心菜属并非单系,桃色无心菜应纳入独缀草属的范畴。此外,还支持将传统无心菜属齿瓣亚属中漆姑无心菜(A.saginoides Maxim.)、匙叶无心菜(A.spathulifolia C.Y.Wu ex L.H.Zhou)及云南无心菜(A.yunnanensis Franch.)归入齿瓣无心菜属的处理,以及将单花亚属中红花无心菜(A.rhodantha Pax&K.Hoffmann)归入独缀草属的处理。形态特征上,花朵单生于枝端这一特征可作为独缀草属区别于齿瓣无心菜属的重要识别特征。

Arenaria L.s.l.is one of the taxonomically difficult large genera in Caryophyllaceae,it was recircumscribed recently and some other genera were segregated from it based on molecular phylogenetic results.Based on morphological evidence,the species Arenaria melandryoides Edgew.was placed previously within A.subgenus Odontostemma(G.Don)Williams or recently within the genera Odontostemma Benth.ex G.Don and Shivparvatia(Edgew.)Pusalkar&D.K.Singh,however the species has never been included in molecular phylogenetic study.The phylogeny of Alsineae using the nuclear ribosomal internal transcribed spacer(nrITS)sequence was reconstructed.The result showed that the monophyly of the genus Odontostemma circumscribed recently was rejected and A.melandryoides was nested deeply within Shivparvatia,thus the specific name S.melandryoides(Edgew.)Satish Chandra and D.S.Rawat should be accepted.Additionally,the transfer of A.saginoides Maxim.,A.spathulifolia C.Y.Wu ex L.H.Zhou and A.yunnanensis Franch.to the genus Odontostemma and A.rhodantha Pax&K.Hoffmann to Shivparvatia were all supported here for the first time in molecular phylogenetic analyses.Morphologically,the solitary flower at the top of stem might be a good diagnostic character to distinguish the genus Shivparvatia from Odontostemma.