Rubus lasiococcus is a North American species of wild blackberry known by the common names roughfruit berry and dwarf bramble.
Rubus lasiococcus is a tangling, prostrate shrub with very slender stolons spreading along the ground and rooting where their nodes come in contact with moist substrate, forming a mat. Some stems grow erect to bear flowers. The leaves are wide, each deeply divided into three lobes, or compound into three toothed leaflets, borne on a petiole a few cm long. The inflorescence is a solitary flower or a pair of flowers with five reflexed sepals and five white petals each up to long. The fruit is a densely hairy red aggregate about across.
It is native to western North America from British Columbia to northern California, where it grows in mountain forests. In the southern half of its range the plant is commonly found in a plant community in the understory of mountain hemlock (Tsuga mertensiana) and Shasta red fir (Abies magnifica var. shastensis).
The berry is edible.