''Rubus strigosus'', the American red raspberry or American raspberry, is a species of ''

Rubus ''Rubus'' is a large and diverse genus of flowering plants in the rose family, Rosaceae, subfamily Rosoideae, with over 1,350 species. Raspberries, blackberries, and dewberries are common, widely distributed members of the genus. Most of the ...

'' native to much of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

. It has often been treated as a

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all specie ...

of the closely related Eurasian '' Rubus idaeus'' (red raspberry or European red raspberry), but currently is more commonly treated as a distinct species. Many of the commercial raspberry

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s grown for their fruit derive from hybrids between ''R. strigosus'' and ''R. idaeus''; see

Raspberry The raspberry is the edible fruit of a multitude of plant species in the genus ''Rubus'' of the rose family, most of which are in the subgenus '' Idaeobatus''. The name also applies to these plants themselves. Raspberries are perennial with ...

for more details.

Classification

Botanists have long debated the taxonomic treatment of the Eurasian and American red raspberries, with some viewing all of these plants as members of a single,

circumboreal The Circumboreal Region in phytogeography is a floristic region within the Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan. It is the largest floristic region in ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

''Rubus idaeus,'' and others recognizing two (or more) species within this group.Fernald doubted this distinction, but Bailey and many other authors rely on it. The two species share many similarities, and probably recently diverged from a common ancestor, leading to differences in taxonomic interpretation, particularly regarding the more intermediate eastern Asian plants. A common current treatment, followed here, is to classify the North American red raspberries as ''Rubus strigosus,'' and include only the Eurasian plants in ''Rubus idaeus.'' When the species are combined, as done in some recent publications, the Eurasian plants are ''Rubus idaeus'' ssp. ''idaeus'' (or ''Rubus idaeus'' var. ''idaeus),'' and the American plants ''R. idaeus'' ssp. ''strigosus'' (or ''R. idaeus'' var. ''strigosus).'' Different interpretations are also sometimes made regarding placement of various eastern Asian populations of this group, by some considered to represent additional varieties or subspecies, if not different species altogether. The most distinctive physical difference among these plants is usual presence of

gland In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

-tipped hairs on first-year canes, petioles, pedicels, and calyces of ''R. strigosus,'' lacking in ''R. idaeus.''

Distribution

''Rubus strigosus,'' as treated here, is widely distributed in North America, particularly the more boreal regions. Some authors also treat various 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''. with the Eurasian plants being ''Rubus idaeus'' ssp. (or var.) ''idaeus''.

Description

''R. strigosus'' is a

perennial plant A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

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 A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

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

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s are produced in late spring on short

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s on the tips of these side shoots, each flower with five white

petal Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...

s long. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

is diameter, red, edible, sweet but tart-flavored, produced in summer or early autumn; in

botanical Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

terminology, it is not a

berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, rasp ...

at all, but an

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of numerous drupelets around a central core.

References

{{Taxonbar, from=Q210156 strigosus Berries Flora of Western Canada Flora of the Western United States Flora of the Rocky Mountains Flora of the North-Central United States Flora of the Great Lakes region (North America) Flora of Eastern Canada Flora of the Northeastern United States Flora of Idaho Flora of California Garden plants of North America Vines Flora of North America Flora without expected TNC conservation status