THE EVOLUTIONARY SIGNIFICANCE OF THE SPECIATION OF<i>EUPHRASIA</i>IN EUROPE

Yeo, P. F.

doi:10.1111/j.1558-5646.1968.tb03473.x

Cited by 28 publications

(14 citation statements)

References 13 publications

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“…Whatever the explanation for the results, the unusual association of diploid characters with tetraploid specific AFLP bands suggests that rare gene exchange can occur between ploidy levels. On the basis of morphological evidence it has been hypothesised that the diploid endemic taxa E. vigursii and E. rivularis have originated following introgression of genes from the inbreeding tetraploid E. micrantha into the outcrossing diploid E. officinalis (Yeo 1968, Silverside 1991. The earlier discovery of a single triploid individual in a mixed population of the two putative parental taxa demonstrates that the initial hybridisation required for this process does occur in the wild (Yeo 1954).…”

Section: Reproductive Barriers Between Diploids and Tetraploidsmentioning

confidence: 99%

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Genetics, taxonomy and the conservation of British Euphrasia

et al. 2007

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In Britain the genus Euphrasia comprises ca 20 diploid and tetraploid plant species, including several endemics. However, their conservation is impeded by taxonomic uncertainty. Analysis of cpDNA and AFLP variation was used to assess their taxonomic status and establish the extent of barriers to gene exchange among them. Differences in ploidy level constitute a very strong barrier to genetic exchange, although this is not absolute. The diploid endemics E. vigursii and E. rivularis form morphologically and genetically definable units which show some level of reproductive isolation. Within tetraploid Euphrasia, the species showed varying degrees of distinctness. Analysis of geographically paired samples from two widespread outcrossing taxa E. arctica and E. nemorosa provides evidence for extensive genetic exchange between them. However AFLP data indicate that this outbreeding species complex possesses a gene pool distinct from that of the widespread inbreeding tetraploids. The widespread and endemic inbreeding tetraploids contain examples of morphologically and genetically definable taxa, but also species whose distinctness is more equivocal. The conservation implications of this study are that species-based action plans are potentially suitable for conservation of the diploid endemics E. vigursii and E. rivularis. In contrast we contend that a species-based conservation framework, developed with reproductively isolated and genetically distinct groups in mind, requires modification for conservation of the complex and dynamic diversity found within the tetraploids. The adoption of 'taxonomic' action plans, designed to protect the evolutionary processes generating Euphrasia diversity, may provide a supplementary solution for conserving this type of variation.

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Section: Reproductive Barriers Between Diploids and Tetraploidsmentioning

confidence: 99%

“…The remaining two taxa are local endemics, E. vigursii and E. rivularis, each with UK Biodiversity Action Plan status. It has been proposed that these local endemics are the product of hybridisation between diploid and tetraploid parents (Yeo 1966(Yeo , 1968.…”

Section: Study Species and Taxonomymentioning

confidence: 99%

Genetics, taxonomy and the conservation of British Euphrasia

et al. 2007

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“…These floral mirnies eontain little or no neetar. Yeo (1968) has mentioned the ease of a European eyebright, Euphrasia micrantha (Serophulariaee), whieh typieally grows with Ca/luna vu/garis (Erieaeeae). The Euphrasia flowers strongly resemble those of Ca/luna, but Euphrasia has little or no neetar.…”

Section: Reproductive Mimicrymentioning

confidence: 98%

Mimicry in Plants

Wiens

1978

Evolutionary Biology

166

161

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“…Yeo (1968) suggests that Euphrasia growing among Calluna is coloured to mimic the much more abundantly visited Calluna. I am suggesting that Centaurea nigra has radiata capitula in mimicry of C. scabiosa where the two species are sympatric.…”

Section: Resultsmentioning

confidence: 99%

COMPETITION FOR POLLINATORS AND EVOLUTION IN CENTAUREA

Lack¹

1976

New Phytologist

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SUMMARYCentaurea nigra s.l. forms a very variable complex which has received extensive taxonomic treatment. From analysis of previous work it is shown that populations growing on chalk and limestone in association with C. scabiosa flower later than those in the more typical habitat of neutral and acid grassland. The rayed form of the capitula is dominant in these populations, whereas elsewhere unrayed capitula predominate. From observations on the relative numbers of visiting insects, competition for pollinators with C. scabiosa is proposed as a major selective factor influencing these changes.

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THE EVOLUTIONARY SIGNIFICANCE OF THE SPECIATION OFEUPHRASIAIN EUROPE

Cited by 28 publications

References 13 publications

Genetics, taxonomy and the conservation of British Euphrasia

Genetics, taxonomy and the conservation of British Euphrasia

Mimicry in Plants

COMPETITION FOR POLLINATORS AND EVOLUTION IN CENTAUREA

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