Phylogenetic Tree of Artemisia Species (A. campestris, A. carruthii, A. dracunculus, A. filifolia and A. ludoviciana) in Kansas Based on Morphological and Anatomical Characteristics

Abstract

Artemisia, a wide spread and diverse genus in the family Asteraceae, includes five native species common in Kansas, particularly in the western half of the state. These include Artemisia campestris (field sagewort), A. carruthii (sagewort), A. dracunculus (tarragon), A. filifolia (Louisiana wormwood) and A. ludoviciana (sand sage). Using both fresh material and herbarium specimens, we completed a comparative morphological and anatomical study of roots, stems, leaves and inflorescences to construct a phylogenetic tree of the Kansas species. Antennaria neglecta was used as an outgroup for the analysis. Morphological measurements were made with a vernier caliper or with a fine metric ruler under a dissecting microscope. For the anatomical study, we examined sectioned material prepared from fresh collections and rehydrated herbarium specimens. There was no significant difference in measurements obtained in specimens from these two sources. A total of 46 characteristics were used to construct a phylogenetic tree of the Kansas species. Our objectives were to compare our tree to the molecular tree published by Watson et al. (2002), which included more than 50 species in the genus, sensu lata, but not A. caruhii, and to place the latter species into the tree. The typologies of our tree and the molecular tree were congruent and we were able to place A. carruhii into the clade they identify as Artemisia subgenus Dracunculus, which also contains A. compestris and A. dracunculus. Both trees identified A. ludoviciana and A. filifolia as sister species in the same clade (their Artemisia subgenus Artemisia).