Flora of North America species comparison

Rubus nutkanus is distinguished from other flowering raspberries by its erect, unarmed stems, simple leaves, large flowers, white petals, glabrous, clavate styles, and yellowish to reddish stipitate glands covering most plant parts. A hybrid with R. odoratus (R. ×fraseri Rehder) is thought to occur in areas of overlap in northern Michigan (E. G. Voss 1972–1996, vol. 2). Varieties and forms have been described based on indument and glandularity of stems, leaves, petioles, pedicels, and sepals (for example, M. L. Fernald 1950). Different variants often occur mixed in the same population and generally do not correspond to definite geographic regions (N. C. Fassett 1941). Plants from coastal California (considered as var. velutinus) tend to have densely hairy leaf abaxial surfaces; this variation may be environmentally induced; other Rubus species show the same pattern (for example, R. spectabilis var. franciscanus) in that area. Wild thimbleberries are collected in Keweenaw Peninsula, Michigan, and are used in beverages and especially for jam.

Rubus nutkanus is typically associated with western North America but was originally described from plants at its eastern range limit in northern Michigan. The Great Lakes populations are disjunct from western mountain populations by around 600 miles.

The name Rubus parviflorus var. grandiflorus Farwell, which applies here, is illegitimate.

(Discussion copyrighted by Flora of North America; reprinted with permission.)