Chromosome Numbers and Taxonomic Notes for North American Species of Antennaria (Asteraceae: Inuleae)

Abstract

Chromosome numbers are presented for 132 populations of 27 taxa and three natu- rally occurring hybrids of Antennaria. Of the 27 taxa, 15 apparently have not been counted before and two counts are new numbers for species previously determined. Twenty taxa consist entirely or partially of sexual diploids (2n = 28): A. arcuata, A. argentea, aromatica, A. corymbosa, A. dimorpha, A. dioica, A. flagellaris, A. Geyeri, A. lanata, A. luzuloides, A. media, A. microcephala, A. microphylla, A. neglecta, A. plantaginifolia, A. racemosa, A. solitaria, A. suffrutescens, A. umbrinella, and A. virginica. Six other species for which counts are not available are thought to exist as sexual diploids, bringing to 26 the total number of sexual diploids in the genus as a whole. Chromosome numbers are also presented for the five heteroploid complexes: A. alpina s.l. (including A. media), A. neodioica s.l., A. parlinii s.l., A. parvifolia s.l., and A. rosea s.l. While A. alpina s.l., A. rosea s.l., and A. neodioica s.l. each consist of one or two euploid chromosome levels, A. parlinii and A. parvifolia each have at least four different levels. Antennaria parvifolia has the highest chromosome number known in the genus, 2n = 140 (decaploid). B-chromosomes were found in A. suffrutescens. Based on the counts presented and karyotypic information, it is hypothesized that the original base number in Antennaria was x = 14. A fourth subspecies of the A. neodioica complex, Antennaria neodioica subsp. howellii, is formally named.