AOBPreview originally published online on August 15, 2005
Annals of Botany 2005 96(5):887-900; doi:10.1093/aob/mci241
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A Morphological Study of the Petunia integrifolia Complex (Solanaceae)
1 Faculty of Horticulture, Chiba University, 648 Matsudo, Matsudo City, Chiba 271-8510, Japan, 2 Center of Environment, Health and Field Science, Chiba University, 6-2-1 Kashiwanoha, Kashiwa City, Chiba 277-0882, Japan, 3 Graduate School of Science and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan, 4 Centro de Pesquisas de História Natural, 618 Rua Jaime Ribeiro Wright, Itaquera, São Paulo 08260-070, Brazil, 5 Facultad de Agronomia, Universidad de la República, Garzón 780, Montevideo, Uruguay and 6 Centro de Investigation de Recursos Naturales, INTA, Las Cabañas y Reseros s/n (1712), Castelar, Prov. de Buenos Aires, Argentina
* For correspondence. E-mail andot{at}faculty.chiba-u.jp
Received: 23 January 2005 Returned for revision: 4 April 2005 Accepted: 20 June 2005 Published electronically: 15 August 2005
• Background and Aims Petunia inflata has been treated taxonomically in various ways: it has been described as an independent species, treated as a synonym of P. integrifolia, and also regarded as a subspecies of P. integrifolia. The present study was designed to resolve the ambiguity involving the P. integrifolia complex (P. integrifolia plus P. inflata).
• Methods Tentative identification (either integrifolia group or inflata group) was carried out in the field based on the observation of live specimens at the restricted type localities. The accuracy of the tentative identification was later tested with principal component and cluster analyses of data obtained by measuring 21 morphological characters on cultivated live specimens sourced from 113 natural populations of the P. integrifolia complex in Argentina, Brazil, Paraguay and Uruguay.
• Key Results There was a clear, statistically significant gap between the morphological measurements of the two groups, ensuring the accuracy of identification carried out in the field except for a probable hybrid swarm. Previously, the condition of the pedicel in the fruiting state was considered an important character distinguishing between these two groups; however, the condition of the pedicel was rather variable in the integrifolia group. The two groups were found to have geographically distinct distributions: the integrifolia group occurred in southern regions, whereas the inflata group occurred in northern regions.
• Conclusions Based on the available evidence, it is suggested that the two groups are allopatric species, P. integrifolia and P. inflata, in agreement with the opinion of Fries (1911).
Key words: Distribution, floral morphology, Petunia, Serra Geral, Solanaceae, South America, speciation