New Approach to the Systematics of the Section Psammiris (Iris, Iridaceae): What Does Chloroplast DNA Sequence Tell Us?

Abstract

Iris sect. Psammiris comprises rhizomatous perennials distributed in the north temperate zone of Eurasia. The systematics of the section are currently based on morphology, and the phylogenetic relationships within it still remain unclear. In the framework of Iris systematics, we conducted molecular and morphological analyses of the currently recognized I. sect. Psammiris species to elucidate the taxonomic composition and relationships within the section. The phylogenetic reconstructions based on sequence variation of four noncoding chloroplast DNA regions support the monophyly of I. sect. Psammiris, which includes I. tigridia, while I. potaninii var. ionantha belongs to I. sect. Pseudoregelia. The proposed novel classification of I. sect. Psammiris recognizes three series: an autonymic series with I. humilis, I. bloudowii, and I. vorobievii and two unispecific series (I. ser. Potaninia with I. potaninii and I. ser. Tigridiae with I. tigridia). In addition, the taxonomic statuses of I. arenaria, I. ivanovae, I. kamelinii, I. mandshurica, I. pineticola, I. psammocola, and I. schmakovii are clarified herein. We provide a revised taxonomic treatment for I. sect. Psammiris, including notes on the types; updated information on species synonymy, distributions, habitats, and chromosome numbers; and a new identification key to the species. Three lectotypes are designated here.

Taxonomic Reinstatement of the Endemic Chinese Species Iris thoroldii (Iridaceae) from I. potaninii and Reassessment of I. zhaoana

“…The morphological description of I. thoroldii was based on a direct examination of the herbarium specimens from K, LE (Annex 1), and NENU, as well as on the images of well-developed plants in flowering and fruiting stages available in the virtual herbaria [50,51] (Annex 1). I incorporated the morphological data of I. potaninii from a recent study [9] and added information on the leaf remnants' length, number of stem leaves, stem leaf shape, bract shape, flower diameter, and the morphology of fall, standard, and seed obtained as a result of extensive field investigations and thorough examination of specimens from LE and VBGI. The terminology used in the descriptions was based on reference [52].…”

“…In China, the genus is represented by approximately 60 species [2,3]. In the past five years, each of the in-depth taxonomic studies of Iris have led to changes in the scope of delimitation and systematic positions of the Chinese species (e.g., [4][5][6][7][8][9]). In fact, there are still some species of which very little is known, or where their actual identity is poorly understood.…”

“…ionantha) [9,48]. The tru I. potaninii has non-curled remnants of leaves, and it is found only in southern Siberia Mongolia, and northern China [9]. Thus, it has become evident that I. thoroldii is errone Crespo et al [25] raised I. potaninii var.…”

“…Recently, it has been suggested, however, that the plants from western China belong to a species that is different from I. potaninii (sub I. potaninii var. ionantha) [9,48]. The true I. potaninii has non-curled remnants of leaves, and it is found only in southern Siberia, Mongolia, and northern China [9].…”

“…ionantha) [9,48]. The true I. potaninii has non-curled remnants of leaves, and it is found only in southern Siberia, Mongolia, and northern China [9]. Thus, it has become evident that I. thoroldii is erroneously synonymized with I. potaninii, as well as the yellow-flowered Tibetan plants are erroneously attributed to I. potaninii, while I. thoroldii is still ignored, and its color forms have not received proper taxonomic treatment.…”