Rubus caesius – Section Caesii

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The Dewberry is a very familiar plant across most of the UK, though much scarcer in Scotland. It is also widespread across temperate parts of Europe. It favours chalk and limestone and is frequently found alongside artificially surfaced roads, tracks and railway embankments. Its main features are the low-growing habit, white-petalled flowers, thin stems which often have a whitish, waxy bloom, leaves with three leaflets and the familiar poorly-formed fruits which also have the whitish coating. Dewberry is variable in appearance and can hybridise with bramble species, especially members of the Corylifolii.

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Flowers are typically 2-2.5cm in diameter. The petals are broadly elliptical, often wider near the base and are frequently crinkled, toothed or mishapen. The stamens are longer than the pale green styles when the flower is viewed side-on, but sometimes almost level. The fine-pointed sepals clasp the fruit as it develops. They are green with white margins (caused by the variation in pubescence) and have scattered to numerous very short-stalked glands.

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The number of drupelets in the fruit varies, but is usually many fewer than in most bramble species.

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The plant has a trailing growth habitat due to its weak stems, so colonies rarely exceed 50cm in height.

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Leaves have three leaflets, comprising the terminal leaflet and two unstalked lateral leaflets. However, the 4th and 5th basal leaflets are often visible as lobes at the base of laterals, but never fully develop. The terminal leaflet is usually ovate in shape and sometimes has a slightly lobed margin. The leaflets are yellowish-green to mid-green in colour and vary from flat and thin to rugose in texture (especially older leaves growing in the sun).

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Leaflets are sparsely hairy on both sides and usually green to pale green below, though sometimes slightly greyish-felted in appearance.

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The stems are round in cross-section, starting green but often appearing nearly white due to the pruinose coating. Later, they turn reddish-brown and the coating may be partly lost or become less noticeable (only just visible in the first photo below). The shortish, slender prickles are slightly angled and occur all round the stem. The density of prickles is variable. Typical plants have no hairs on the stem but sometimes there are sparse or fairly numerous very short-stalked glands and acicles. In the photo below note the lanceolate shaped stipule at the base of the leaf stalk which is broader than the filiform stipules of most brambles (except Corylifolii).

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