Convergent origin of the narrowly lanceolate leaf in the genus Aster—with special reference to an unexpected discovery of a new Aster species from East China

Abstract

Narrowly lanceolate leaves occur frequently in the genus Aster. It was often employed as a distinguishing character in the taxonomy of this genus. The origin of this particular leaf shape, however, has never been investigated using comparative methods. In this study, we reconstructed a comprehensive phylogeny that includes most species of Aster with narrowly lanceolate leaf. We then gathered data on riparian habitats and the presence or absence of narrowly lanceolate leaves, and investigated the evolutionary association between them in a phylogenetic context. Our analysis indicated that the species with narrowly lanceolate leaves are nested in unrelated lineages of the genus Aster, implying that they originated independently several times. Using Pagel’s comparative method of discrete data, we demonstrated a significant correlation between riparian habitats and narrowly lanceolate leaves. We further inferred the sequence of transition of the two characters. This analysis indicated that the sequence of evolution of riparian habitat and narrowly lanceolate leaf form was usually uncertain, but some positive results showed that the occurrence of riparian habitats may not precede the evolution of narrowly lanceolate leaf form. This study provided new insights into the adaptive evolution in a mega-diverse family. In addition, Aster tonglingensis, an unexpected new species with narrowly lanceolate leaves, was discovered and established based on the evidence from morphology, micromorphology and molecular phylogeny.

Aster quanzhouensis (Asteraceae), a new riparian species from eastern China

“…Aster quanzhouensis is known only from two populations (Dehua and Yongchun counties) restricted to Quanzhou, Fujian, China, while A. tonglingensis is restricted to Mt. Tongling Natural Reserve, Wencheng county, Zhejiang (Zhang et al 2019). These two species occupy the same ecological conditions, but are geographically separated by a distance of 400 km.…”

“…Comparison of Aster quanzhouensis and A. tonglingensis. The data of the latter species were taken fromZhang et al (2019).…”

Aster sanqingshanica (Asteraceae, Astereae), a new species from Jiangxi, China

“…Nuclear ribosomal ITS and ETS sequences of 66 taxa, representing major clades of the genus Aster and its relatives (Li et al 2012, 2017, 2020, Zhang et al 2015, 2019, Xiao et al 2019a, b2019b), were downloaded from GenBank (Supporting information). Additionally, six newly sequenced accessions included two samples of the new taxon (Supporting information).…”

“…China has over 123 accepted names of Aster (Chen et al 2011) and its southwest region is the distribution centre of this genus (Li et al 2012). In China, eight new Aster species have been described the last five years (Zhang et al 2015, 2019, Li et al 2017, 2020, Xiao et al 2019a, b2019b, 2020, Xiong et al 2019).…”

Characterization of the complete plastome of Aster pekinensis (Asteraceae), a perennial herb

“…Based on combined sequences of ITS, ETS, and trnL-F , the recent phylogenetic tree demonstrated that A. pekinensis was sister to A. indicus (Zhang et al. 2019 ). In this study, we reported the complete plastome of A. pekinensis , which will be helpful for species identification and the phylogenetic analysis of the genus Aster .…”