Morphological and isoenzyme divergence in Gambelia (Scrophulariaceae): species delimination and biogeographic relationships

To compare hypothesized species boundaries in Gambelia to patterns of differentiation inferred from morphology and isozymes, we examined nine populations for divergence at 22 isozyme loci and 29 OTU's/populations for morphological divergence using 20 characters. Thirteen quantitative and seven...

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Bibliographic Details
Published inSystematic botany Vol. 18; no. 3
Main Authors Elisens, W.J, Nelson, A.D
Format Journal Article
LanguageEnglish
Published 01.07.1993
Subjects
AMERICA DEL NORTE
AMERIQUE DU NORD
ANATOMIA DE LA PLANTA
ANATOMIE VEGETALE
DISTANCE GENETIQUE
DISTANCIA GENETICA
DISTRIBUCION NATURAL
DISTRIBUTION NATURELLE
ESPECE
ESPECIES
GENE
GENES
GENETICA
GENETIQUE
ISOENZIMAS
ISOENZYME
LOCI
LOCUS
SCROPHULARIACEAE
TAXONOMIA NUMERICA
TAXONOMIE NUMERIQUE
VARIACION GENETICA
VARIATION GENETIQUE
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Summary:To compare hypothesized species boundaries in Gambelia to patterns of differentiation inferred from morphology and isozymes, we examined nine populations for divergence at 22 isozyme loci and 29 OTU's/populations for morphological divergence using 20 characters. Thirteen quantitative and seven qualitative characters were analyzed using clustering (UPGMA) and ordination (PCA, CVA) methods. Placement of North American shrub snapdragons in Gambelia separate from southern hemisphere species (Galvezia s. str.) was supported by numerous qualitative morphological and genetic differences. Within Gambelia, the pattern of morphological and isozyme variation is most concordant with recognition of two species, G. speciosa and G. juncea, based on the phylogenetic species concept. Each species can be defined by several invariant and unique morphological and isozyme characters. Delimitation of intraspecific taxa in G. speciosa is unwarranted, because no consistent interpopulation differentiation was observed. Recognition of segregate species within the G. juncea complex of Baja California and Sonora also was not supported. No constant morphological differences were observed for either G. glabrata or G. rupicola. Biogeographic and systematic data support hypotheses that the California Island endemic G. speciosa is relictual, that disjunct Sonoran populations of G. juncea were established recently, and that populations of G. juncea from the Cape Region of Baja California have been isolated since the Holocene
Bibliography:F50
F30
9428135
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ISSN:0363-6445
1548-2324