Taxonomy of Echium (Boraginaceae) species from Cape Verde Islands
Maria M. Romeiras A B D , Lia Ascensão C , Maria C. Duarte B , Maria A. Diniz B and Maria S. Pais AA Instituto de Ciência Aplicada e Tecnologia, UPMBB, Faculdade de Ciências, Campo Grande, 1749-016 Lisboa, Portugal.
B Instituto de Investigação Científica Tropical, Travessa Conde da Ribeira 9, 1300-142 Lisboa, Portugal.
C Universidade de Lisboa, Faculdade de Ciências, DBV, Centro Biotecnologia Vegetal, Campo Grande, 1749-016 Lisboa, Portugal.
D Corresponding author. Email: mariaromeiras@net.sapo.pt
Australian Systematic Botany 21(1) 26-38 https://doi.org/10.1071/SB07016
Submitted: 20 April 2007 Accepted: 14 January 2008 Published: 3 April 2008
Abstract
The morphological variation of endemic species from the Macaronesian Islands has long attracted attention of many taxonomists. The taxonomy of the endemic Echium L. species (E. hypertropicum Webb, E. stenosiphon Webb and E. vulcanorum A.Chev.) from Cape Verde Islands was revised, on the basis of in situ collected material and on herbarium specimens. Our results revealed that the patterns of morphological variation correspond closely to the geographic localisation of the islands groups, and that habit and floral morphology are important for distinguishing the two southern taxa, E. hypertropicum and E. vulcanorum, from the northern species, E. stenosiphon. This species has the same ecological preferences (e.g. altitude; exposition; soil type) in São Nicolau, São Vicente and Santo Antão Islands. However, the differences in indumentum observed among E. stenosiphon specimens account for the occurrence of different taxonomic groups distributed in these Northern Islands. The two southern species, E. hypertropicum and E. vulcanorum, are morphologically similar, but have different ecological preferences, a pattern of variation similar to other Macaronesian Echium species. Furthermore, the morphological variation observed among the three Cape Verde species, discussed within the general context of Echium taxonomy and closely related genera (e.g. Lobostemon, Echiostachys and Pontechium), suggests that the systematic relationships are beyond the actual circumscription of these genera.
Acknowledgements
The authors are grateful to the two anonymous reviewers for the constructive suggestions on the first version of this paper. Also, we are grateful to D. Batista, M. Sebastiana, H. Cotrim and F. Monteiro, namely for helpful comments and organisation of the figures. The authors are grateful to the INIDA from Cape Verde for logistic support. This study was supported by Fundação para a Ciência e Tecnologia (FCT) from Portugal by awarding the grant PRAXIS XXI BD/19596/99.
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