Phyletic Trends in Sections Eublepharis and Calliopsis of the Genus Coreopsis (Compositae)

Abstract

Artificial hybridization, fertility of interspecific and intersectional hybrids, chromosome numbers, and trends in habit and morphology in taxa of sections Eublepharis and Calliopsis of the genus Coreopsis are used to consider the sectional relationships and to derive a presumed phylogeny for the two sections. The two sections are closely related and show a low level of interfertility, but this level is as high as in some interspecific crosses within sections. The sections differ in base chromosome number and achene winging. The problematic C. rosea evidently should remain in section Eublepharis. Both sections probably arose from x = 13 stock resembling C. integrifolia or C. pubescens. Descending aneuploidy was involved in the derivation of section Calliopsis, while chromosome evolution in section Eublepharis has involved polyploidy.

Phylogeny of Eastern North American Coreopsis (Asteraceae‐Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution

“…Smith's (1983) drawing has C. rosea near the base and Jansen et al (1987) place C. rosea (together with C. nudata) as sister to the remaining species of the section. The tree of Jansen et al (1987) places C. integrifolia sister to the remaining taxa (C. falcata, C. floridana, C. gladiata, C. linifolia) of the section; Smith's (1983) drawing has it as the most basal species in the section. It shares with C. nudata ligules that vary from orange-yellow to rose, which contrast with the typical yellow ligules found in other Coreopsis.…”

“…The monospecific sect. Therefore, hypotheses of relationships at the intrasectional level have been formulated primarily from inexplicit methods in which the evolutionary advancement was determined for species based on whether they exhibited ''primitive'' or ''advanced'' states for 12-15 mostly morphological characters (Smith, 1982(Smith, , 1983E. 1).…”

“…Calliopsis (three species), the two primarily eastern North American species, C. leavenworthii and C. tinctoria, have been viewed as sister to the northern Mexican species C. paludosa (Smith, 1983;Jansen et al, 1987). Calliopsis (three species), the two primarily eastern North American species, C. leavenworthii and C. tinctoria, have been viewed as sister to the northern Mexican species C. paludosa (Smith, 1983;Jansen et al, 1987).…”

“…Our results are concordant with earlier studies in placing this distinctive species as a basal element in the section. The three species C. floridana, C. gladiata, and C. linifolia have been viewed as a closely related group (Smith, 1983;Jansen et al, 1987). Also, C. rosea, which occurs from Maryland to Nova Scotia, has a more northerly distribution than other species in sect.…”

“…Also, C. rosea, which occurs from Maryland to Nova Scotia, has a more northerly distribution than other species in sect. Additional field and laboratory studies are needed to elucidate relationships in this species complex (Smith, 1975(Smith, , 1976(Smith, , 1983. The tree of Jansen et al (1987) places C. integrifolia sister to the remaining taxa (C. falcata, C. floridana, C. gladiata, C. linifolia) of the section; Smith's (1983) drawing has it as the most basal species in the section.…”