Boysenberry

Rubus ursinus × R. idaeus
Boysenberries in various stages of development
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Rosaceae
Genus:	Rubus
Subgenus:	Rubus
Species:	R. ursinus × R. idaeus
Binomial name
Rubus ursinus × R. idaeus

The boysenberry /ˈbɔɪzənbɛri/ is a cross between the European Raspberry (Rubus idaeus), a European blackberry (Rubus fruticosus), an American dewberry (Rubus aboriginum) and the Loganberry (Rubus × loganobaccus).

It is a large 8.0-gram (0.28 oz) aggregate fruit, with large seeds and a deep maroon color, which changes to the typical boysenberry color when the fruit is cooked and made into jam and pie.

The exact origins of the boysenberry are unclear but the most definite records trace the plant as it is known today back to grower Rudolph Boysen, who may have obtained the dewberry/loganberry parent from the farm of a man by the name of John Lubben (who called it a "lubbenberry"), who in turn may have obtained it from Luther Burbank.

In the late 1920s, George M. Darrow of the USDA began tracking down reports of a large, reddish-purple berry that had been grown on Boysen's Northern California farm. Darrow enlisted the help of Walter Knott, a Southern California farmer who was known as a berry expert. Knott had never heard of the new berry, but he agreed to help Darrow in his search.

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Wikipedia