Betula nana L., a branch from three adjacent individuals (Finland, Enontekiö, Kilpisjärvi, 1979) – Image: Harri Harmaja (scanned from dried specimens). – In a locality in Finnish Lapland, adjacent individuals of this dwarf-sized birch species were found to display – no doubt hereditary – differences in some characters such as the leaf size. The leaf size was consistent within each the three depicted individuals. None of them appears to be any hybrid. The leaf blade diametre of the three plants is (from the left) 0.5-0.7, 0.8-1.4, and 1.5-2.5 cm, respectively. The middle size is apparently the "normal" one in Finland. The variability of the leaf size of B. nana (Betulaceae) in Finland has been noted before, but generally the variability of the species deserves more attention. Among other things, the possible introgressive influence of B. pubescens Ehrh. ssp. czerepanowii (N.I.Orlova) Hämet-Ahti (ssp. tortuosa auct.) to B. nana should be considered. In Russia, it has recently been expressed that some B. nana populations in Kola Peninsula possess traits of the extralimital B. tundrarum Perf. (Tzvelev, N. 2002: O rodakh Betula L. i Alnus Mill. (Betulaceae) v vostochnoj Evrope. – Novosti sist. vyssh. rast. 34: 47-73.).
Created August 5, 2004.