Betula glandulosa (a rare CNPS list 2.2 plant) is a spreading to upright deciduous shrub. Plants have glabrous twigs with large, warty, resinous glands, and small, rounded leaves with dentate to crenate margins. Botanists have treated the closely related dwarf birches that range throughout boreal North America and Eurasia under a confusing set of names, including B. glandulosa, B. glandulifera, B. nana, and B. pumila. In addition, the plants vary regionally and hybridize (Furlow 1997). Plants in California are B. glandulosa at the species’s southwestern limit (see revised Jepson Manual, UCB 2007).

Stands of B. glandulosa are ecologically most closely related to those of Salix boothii and S. eastwoodiae, and they tend to segregate from the willow stands by occurring in more organically rich stream deposits adjacent to wet meadows. Stands also occur along streams with moderately steep gradients adjacent to upland conifer stands, including those of the Abies concolor alliance (S. Smith 1998). Birch stands are susceptible to livestock grazing; they decrease in extent and frequency with continuous or late-season grazing and transition to herbaceous stands with Bistorta bistortoides, Muhlenbergia spp., and Trifolium longipes (S. Smith 1998).

S. Smith (1998b) described a Betula glandulosa community type from three plots in the Warner Mountains (M261Gf ) and Southern Cascades (M261D) where associated species include Salix eastwoodiae and various tall herbs. Recent observations in the Dismal Swamp area of the northern Warner Mountains suggest there are at least 3 small stands (< 0.5 ha) that occur within a 1 km radius of each other (Hickson et al. 2007). These stands associate with larger S. bebbiana and S. boothii stands and those of the Carex nebrascensis, Populus tremuloides, and Veratrum californicum alliances. B. glandulosa also occurs in the Southern Cascades (M261D) in Lassen, Plumas, and Tehama Cos. We need additional sampling and analysis to verify its distribution and the range of habitats in which it occurs in California.