Salix pentandra L. (Salicaceae), twigs of two trees (Finland, Äänekoski, Pudasjärvi, 1979; ♀ on the left, ♂ on the right). – Image: Harri Harmaja (scanned from dried specimens). – Most probably an example of gender-linked leaf dimorphism is concerned: as compared with the female tree, the leaves of the male tree are narrower and with somewhat more acuminate apices. The difference proved to be constant: not only the illustrated two trees but all the other trees of both genders in the locality obeyed this rule which would exclude a random coincidence. This dimorphism has not been reported in the species before. However, apparently this phenomenon is present in the local population only. A screening through the Nordic collections of S. pentandra in our herbarium (H) did not reveal any clear-cut correlation between the gender and variability of leaf morphology.
Created August 29, 2004. Latest revision July 24, 2006.