About Rubus idaeus L.
Plants of Rubus idaeus are generally perennials, which produce biennial stems called "canes" that grow from a permanent perennial root system. In its first year, a new, unbranched stem called a "primocane" grows vigorously to reach its full height of 1.5–2.5 m (5.0–8.3 feet). This first-year stem bears large pinnately compound leaves with five or seven leaflets, and usually does not produce any flowers. In its second year, the stem is called a "floricane"; it does not grow any taller, but instead develops several side shoots that bear smaller leaves with three or five leaflets. Flowers develop in late spring on short racemes at the tips of these side shoots. Each flower is around 1 cm (0.4 inches) in diameter, with five white petals. The fruit is red, edible, and has a sweet yet tart flavour, and ripens in summer or early autumn. In botanical terms, it is not a true berry; instead it is an aggregate fruit made up of numerous small drupelets arranged around a central core. In raspberries, which belong to various species of Rubus subgenus Idaeobatus, the drupelets separate from the core when the fruit is picked, leaving the fruit hollow. By contrast, in blackberries and most other Rubus species, the drupelets remain attached to the core when picked. On average, the fruit of R. idaeus persists for 12 days, and each fruit contains an average of 35.2 seeds. Wild R. idaeus fruits have an average water content of 76.3%, and their dry weight is made up of 39.6% carbohydrates and 2.2% lipids. R. idaeus is cultivated primarily for its fruits, and is occasionally grown for its leaves, roots, or other plant parts.
