Rubus subintegribasis – Series Sylvatici

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This bramble is endemic to Britain where it restricted to south-east Dorset and south-west Hampshire, usually being found on lowland heathland (there is an outlying record mapped for Wiltshire in the Atlas of British & Irish Brambles). Its key features are the white or pale pink obovate petals, short stamens, shiny green sepals with white borders and obovate leaflets with a short apex.

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Rubus subintegribasis is eglandular (only sessile and subsessile glands present) and almost glabrous, so resembles some species in Section Rubus, such as Rubus plicatus. The panicle has some 3-foliate leaves below and usually a single leaflet above, which sometimes overtops the inflorescence. The rachis is slightly flexuose and has medium to long declining or slightly curved prickles like those on the stem and is hairy above. The lower floral branches are usually long, slender and strongly ascending. The panicle is relatively few-flowered. This is typically a low-growing bramble but it sends out robust ascending stems and like many brambles is adapted to growing up through other shrubby vegetation.

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Flowers are about 2cm across with white petals which start off a creamy pale pink colour, barely detectable when fully open. Petals are distinctly obovate in shape, 11-12 x 7mm, often appearing almost squared off at the apex, which is usually irregularly and finely toothed.

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Sepals are broadly white-bordered due to the thickly pubescent margins contrasting with the shiny and less hairy green centres. They are short-pointed, usually patent at flowering (with upturned tips), though sometimes loosely reflexed. They also bear some short, inconspicuous acicles. The stamens are shorter than or about level with the styles and typically splay out so that the styles and developing carpels are always visible. The anthers are glabrous or may have a few hairs. Filaments may sometimes be pale pink.

subintegribasis

The styles are greenish yellow, but can be tinged pinkish at the base, visible in the flower on the left, below. The young carpels are glabrous (sometimes hairy?) and the receptacle is hairy.

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Leaves have three, or more usually five leaflets, which are thin in texture, almost glabrous above but typically a dull or matt green colour. Younger leaflets are brighter, more yellow-green and plicate, but mature leaflets are flat. The toothing is quite shallow and narrow. The terminal leaflet is obovate, about 7-8 x 4-5cm, or on weak stems only 6 x 3cm. The base is entire or sometimes cordate. The apex is relatively short and cuspidate and there is often a suggestion of a shallow lobe on each side of the apex (visible in the leaf on the right, below). This often gives the terminal leaflet a shouldered appearance. The petiolule is short to long, and the leaflets may overlap slightly.

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Some leaves have an almost oblong terminal leaflet with straight sides.

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Leaflets are thinly pubsecent on the veins below.

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The first year stem has sparse short hairs and sessile/subsessile glands. It is angled and slightly furrowed, green in colour with some reddish brown streaks if exposed to the sun and pale striations. Prickles are frequent to numerous on the angles, a little shorter to longer than the stem diameter, declining or slightly curved, pale yellow with long reddish bases.

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