| Betula nana subsp. exilis (Sukatsch.) Hult. | |||
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| Family | Betulaceae — APG family: Betulaceae | ||
| Synonyms | Betula exilis Sukatsch., Betula glandulosa var. sibirica (Ledeb.) Blake, Betula nana var. sibirica Ledeb., Betula tundrarum Perfiljev. | ||
| Common name | dwarf birch | ||
| Description | Strongly branching, decumbent dwarf shrub; young twigs covered with resin spots; leaves dark green above, paler beneath, short-petiolated, 0.5-1 cm long, orbicular or somewhat broader than long, sometimes with subcordate base, crenate all around, glabrous or with a few glands on nerves; bracts lacking resiniferous hump on back, with 3 nearly parallel lobes, the median longer than the lateral; nutlets with wings about half as broad as body. | ||
| Ecology | Tundra, bogs. B. nana described from the mountains of Lapland, the bogs of Sweden and Russia. Broken line on circumpolar map indicates range of subsp. nana. | ||
| Taxonomy notes | Subsp. exilis forms complete introgression with B. glandulosa where ranges over- lap. Hybrids with the large-leaved tree birches, recognized by large, more or less rounded, more or less crenate leaves, are not rare. |
This is a digital representation of Eric Hultén’s ‘Flora of Alaska and Neighboring Territories: A Manual of the Vascular Plants’, which was published by Stanford University Press in 1968. The book was digitized by C. Webb (at UAMN) as part of the Flora of Alaska project, with funding by the US NSF (Grant 1759964 to Ickert-Bond & Webb), and with permission of Stanford University Press. Data and images © 1968 Board of Trustees of the Leland Stanford Jr. Univ. Usage licence: Creative Commons BY-NC-SA 4.0. NB: You may find OCR errors; please refer to the hard-copy if in doubt.