| Betula nana L. | |
| Publ. & Syn. | L., Sp. Pl.: 983 (1753). Described from northern Europe and Russia. Lectotype (LINN): Herb. Linn. 1109.9 (Jonsell and Jarvis 1994: 153). |
| Notes | Two major races of Betula nana have been accepted for a long time: the very broadly amphi-Atlantic subsp. nana and the similarly broadly amphi-Beringian subsp. exilis. These two races are fairly well separated morphologically and find support in molecular data (Eidesen 2007, AFLP). Two other races have been described from more restricted parts of Russia and are disputed: subsp. tundrarum and subsp. perfiljevii. Yurtsev commented that these are not recognized in Russia any more, that subsp. tundrarum is considered an extreme form of B. nana subsp. nana, and that subsp. perfiljevii should be excluded altogether. I agree with exclusion of subsp. perfiljevii but perhaps not with that of subsp. tundrarum, see below. Tzvelev (2002) accepted B. tundrarum and he accepted an additional northeastern Russian species, B. sukatschewii Soczava, about which we have no information. We enter a var. tundrarum for reasons given below. |
| Chromosomes | (1) 42 (3x). - Siberia (N), Far East (N). - At least three reports. (2) ca. 48. - Siberia (N). - Zhukova et al. (1973). (2) 56 (4x). - Far East (N). - At least four reports. |
| Geography | Circumboreal-polar. |
| Parent taxon | Betula L. |
| Child taxa |
Betula nana subsp. exilis (Sukaczev) Hultén Betula nana subsp. nana Betula nana var. tundrarum (Perfil.) Elven comb. et stat. nov. |
| PAF ID | 610212 |