List of Betula species

Subgenera of genus Betula (birch), are;

Subgenus Betulenta - Wintergreen oil birches

Bark on twigs rich in methyl salicylate (oil of wintergreen). Female catkins erect.

  • Diploid (2n = 28).
    • Betula lenta - Sweet birch or cherry birch
      • Betula lenta subsp. uber - Cherry Creek birch
  • Hexaploid (6n = 84).
  • Decaploid (10n = 140).
  • Duodecaploid (12n = 168).
    • Betula megrelica -
  • chromosome number not reported
    • Betula corylifolia - Hazel-leaf birch
    • Betula grossa - Japanese cherry birch
    • Betula insignis -

Subgenus Betulaster - Large-leaf birches

Bark on twigs contains some methyl salicylate. Female catkins pendulous.

Subgenus Neurobetula - Costate birches

Bark on twigs without methyl salicylate. Female catkins erect.

  • Diploid (2n = 28).
    • Betula calcicola -
    • Betula chichibuenis -
    • Betula costata - Korean birch[1]
    • Betula nigra - River birch or black birch
    • Betula potaninii - Potanin's birch
  • Tetraploid (4n = 56).
    • Betula albosinensis - Chinese red birch
      • Betula albosinensis var. septentrionalis - North Chinese red birch
    • Betula ermanii - Erman's birch
    • Betula jacquemontii (B. utilis subsp. jacquemontii) - White-barked Himalayan birch
    • Betula utilis - Himalayan birch
  • Hexaploid (6n = 84).
  • Octoploid (8n = 112).
  • chromosome number not reported
    • Betula fargesii - Farges's birch
    • Betula schmidtii - Schmidt's birch
  • chromosome number unknown

Subgenus Betula - Typical birches

Bark on twigs without methyl salicylate. Female catkins pendulous.

  • Diploid (2n = 28).
  • Tetraploid (4n = 56).
    • Betula celtiberica - Iberian white birch
    • Betula pubescens - White birch, European white birch or downy birch
      • Betula pubescens subsp. tortuosa - Arctic white birch
  • Pentaploid (5n = 70).
  • Hexaploid (6n = 84).
    • Betula papyrifera - Paper birch, canoe birch or American white birch (sometimes tetraploid or pentaploid)

Subgenus Chamaebetula - Dwarf birches

Small shrubs with small rounded leaves. Female catkins pendulous.

Notes

There is no consensus at all on species limits in Betula, with different authors differing wildly in what species they accept, from under 30 species, to over 60. The above (incomplete) list was compiled from the references cited below. Birches will hybridise very freely, particularly in cultivation but also in the wild where conditions and species present permit. While differing chromosome number (diploid, tetraploid, etc.) may reduce interbreeding, it is not an absolute bar to it. Many botanists regard differing chromosome number as a specific discriminant, though not all do so (e.g. some include B. cordifolia and B. neoalaskana as varieties within B. papyrifera).

gollark: https://web.archive.org/web/20171201033424/https://standards.cta.tech/kwspub/published_docs/CTA-861-G_FINAL_revised_2017.pdf
gollark: You can have the SBC transmit different *modes*, then, I think each resolution/framerate/color depth/etc is given a mode number of some sort.
gollark: At worst it might be sending the wrong resolution/etc, and you can force override that.
gollark: > ballsystemlord is saying they can use different protocols that may not be supportedThis is probably inaccurate.
gollark: I don't know exactly what this graph is saying, but modern ryzens definitely have better single thread performance than older threadrippers and possibly old Intel stuff.

References
  1. English Names for Korean Native Plants (PDF). Pocheon: Korea National Arboretum. 2015. p. 373. ISBN 978-89-97450-98-5. Archived from the original (PDF) on 25 May 2017. Retrieved 16 December 2016 – via Korea Forest Service.
  2. Wolfe, Jack A. & Wehr, Wesley C. 1987. Middle Eocene Dicotyledonous Plants from Republic, Northeastern Washington. United States Geological Survey Bulletin 1597:13
  3. Crane P.R. & Stockey R.A. 1987; "Betula leaves and reproductive structures from the Middle Eocene of British Columbia, Canada." Canadian Journal of Botany 65(12): 2490-2500.
  • Bean, W. J. 1976, 1988. Trees & Shrubs hardy in the British Isles. Eighth edition, revised, vol. 1 (1976) & Supplement (1988); editor D. L. Clarke.
  • Hunt, D. 1993. Betula. Proceedings of the IDS Betula Symposium 2-4 October 1992. International Dendrology Society.
  • Li, J., Shoup, S. & Chen, Z.; Shoup, Suzanne; Chen, Zhiduan (2007). "Phylogenetic Relationships of Diploid Species of Betula (Betulaceae) Inferred from DNA Sequences of Nuclear Nitrate Reductase". Systematic Botany. 32 (2): 357–365. doi:10.1600/036364407781179699.
  • Rushforth, K. D. 1999. Trees of Britain & Europe. Collins. (Useful details on chromosome numbers of many European & Asian birches).
  • Skvortsov, A. K. 2002. A new system of the genus Betula. Byulleten Moskovoskogo Obshchestva Ispytatelei Prirody Otdel Biologie 107: 73–76.
  • Flora of North America online - Betula.
  • Grimshaw, J. 2009, New Trees, Recent introductions to cultivation. Kew Publishing

See also
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