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Chocolate Raspberry Cake

Rubus strigosus, the American Red Raspberry or American Raspberry, is a species of Rubus native to most of North America. It has been widely treated as a variety or subspecies of the closely related Eurasian Rubus idaeus (Raspberry or European Raspberry), but is increasingly being treated as a distinct species.

Distribution

Rubus strigosus is widely distributed in North America. Some authors also treat raspberries in eastern Asia, east from the Aerhtal Shan (Altai) Mountain Range in Mongolia to Dongbei (Manchuria) and Japan in this taxon (where it is suggested to have originated along with a great deal of the North American flora), but others include all Asian raspberries in R. idaeus. The two species probably recently diverged from a common ancestor and this has led many taxonomists to refer to them interchangeably or sometimes as a variety of the other such as R. idaeus L. var. strigosus (Michx.) Maxim. The plant is named R. strigosus in the floras of Nova Scotia and New Brunswick, and by other Maritime field researchers.

Description

Rubus strigosus is a perennial plant which bears biennial stems ("canes") from the perennial root system. In its first year, a new stem grows vigorously to its full height of 0.5–2 m, unbranched, and bearing large pinnate leaves with three or five (rarely seven) leaflets; normally it does not produce any flowers. In its second year, the stem does not grow taller, but produces several side shoots, which bear smaller leaves with three leaflets.

The flowers are produced in late spring on short racemes on the tips of these side shoots, each flower with five white petals 4–7 mm long. The fruit is 1–1.2 cm diameter, red, edible, sweet but tart-flavored, produced in summer or early autumn; in botanical terminology, it is not a berry at all, but an aggregate fruit of numerous drupelets around a central core.

Many of the commercial Raspberry cultivars grown for their fruit derive from hybrids between Rubus strigosus and R. idaeus; see Raspberry for more details.

Taxonomy

Many taxonomists believe that R. strigosus Michx. is the same species as the European Rubus idaeus L. These two are the most common members of the subgenus Idaeobatus and can be difficult to differentiate; the most distinctive physical difference being the gland-tipped hairs on first-year canes, petioles, pedicels and calyces of R. strigosus. This character had been refuted previously by Fernald, but Bailey's sheer volume of taxonomic work with Rubus is more reliable.



Rubus strigosus

Rubus strigosus near Matanuska Glacier, Alaska

Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Rosales
Family: Rosaceae
Genus: Rubus
Subgenus: Idaeobatus
Species: R. strigosus

Binomial name
Rubus strigosus

Related : Raspberry