A morphological study of the Petunia integrifolia complex (Solanaceae).
OBJECTIVE
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.


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).
Ando
Toshio
T
Faculty of Horticulture, Chiba University, 648 Matsudo, Matsudo City, Chiba 271-8510, Japan. andot@faculty.chiba-u.jp
Ishikawa
Nobuyuki
N
Watanabe
Hitoshi
H
Kokubun
Hisashi
H
Yanagisawa
Yoshiki
Y
Hashimoto
Goro
G
Marchesi
Eduardo
E
Suárez
Enrique
E
D049628:Body Size; D016000:Cluster Analysis; D035264:Flowers / Q000033:anatomy & histology*; D032306:Petunia / Q000033:anatomy & histology* / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D013020:South America