Betula glandulosa

Taxobox
name = American Dwarf Birch
status = secure
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Fagales
familia = Betulaceae
genus = "Betula"
subgenus = "Chamaebetula"
species = "B. glandulosa"
binomial = "Betula glandulosa"
binomial_authority = Michx.

"Betula glandulosa", American Dwarf Birch, also known as Resin Birch or Shrub Birch, is a species of birch native to North America, occurring in arctic and cool temperate areas from Alaska east to Newfoundland and southern Greenland, and south at high altitudes to northern California and Colorado in the west, and locally south to northern New York in the east. In the Arctic it occurs down to sea level, while in the south of the range, it grows as high as 3400 m altitude. In Mid October 2007 a thicket of this plant was observed in flower in the foothills behind Palo Alto, California amidst Oaks, Bay Laurel and Manzanita.

American Dwarf Birch is a multi-stemmed shrub typically growing to 1-3 m tall, often forming dense thickets. The trunks are slender, rarely over 5-10 cm diameter, with smooth, dark brown bark. The leaves are nearly circular to oval, 0.5-3 cm long and 1.2.5 cm broad, with a toothed margin. The fruiting catkins are erect, 1-2.5 cm long and 5-12 mm broad.

It is closely related to the Dwarf Birch ("Betula nana"), and is sometimes treated as a subspecies of it, as "B. nana" subsp. "glandulosa". It is distinguished from typical "B. nana" by the presence of glandular warts on the shoots and longer leaf petioles. Hybrids with several other birches occur.

References

* [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500248 Flora of North America: "Betula glandulosa"] , [http://www.efloras.org/object_page.aspx?object_id=5739&flora_id=1 RangeMap]
*Hunt, D. (1993). "Betula. Proceedings of the IDS Betula Symposium 2-4 October 1992". International Dendrology Society.