Ranunculus bulbosus L. - Bulbous Buttercup

Ranunculus bulbosus plant

Family - Ranunculaceae

Stems - To +60cm tall, erect, single or typically multiple from the base, fistulose, herbaceous, typically purplish, branching, antrorse appressed pubescent or slightly spreading pubescent, from a thickened corm-like base and thickened roots.

Ranunculus bulbosus stemPortion of stem.

Ranunculus bulbosus baseRoots and base of plant.

Leaves - Alternate, petiolate below, becoming sessile above, the bases of the basal leaves spreading and surrounding the corm-like base of the plant. Petioles to +15cm long, long antrorse pubescent, with a deep adaxial groove. Stipule-like appendages at the base of the leaves scarious, sometimes with two squarish auricles at the apical end. Leaf blades pubescent above and below, trifoliolate, ovate in outline, to +6cm long, +7cm long. Leaflets of the basal leaves often 3-lobed again. Ultimate divisions of leaves acute. Terminal leaflet on petiolule to +2cm long. Lateral leaflets on petiolule to 6-7mm long. Terminal leaflet slightly larger and more deeply lobed. Leaves reduced upward, becoming sessile and just 3-lobed. Lobes entire, linear to oblanceolate, subacute, pubescent.

Ranunculus bulbosus leaves

Inflorescence - Axillary and terminal pedunculate flowers. Peduncles to +15cm long, appressed pubescent, green, carinate or not, a small leaf occasionally present on peduncle or not.

Flowers - Petals 5, shiny yellow adaxially, pale yellow below, glabrous, to 1.5cm broad and long, broadly obovate to orbicular. Stamens many (+50), borne below the carpels. Filaments to +7mm long, glabrous, yellowish. Anthers yellow, to 3mm long, oblong. Carpels glabrous, compressed, green, to 3mm long in flower, quickly expanding in fruit. Receptacle pubescent. Sepals 5, reflexed in flower, greenish yellow, to 1.5cm long, 5mm broad at the base, pilose adaxially, glabrous adaxially, subulate-triangular, often reddish at the apex and/or with a red midvein.

Ranunculus bulbosus flower

Ranunculus bulbosus sepalsSepals.

Ranunculus bulbosus achenesDeveloping achenes.

Flowering - April - June.

Habitat - Wet open pastures, orchards, grassy open fields, roadsides.

Origin - Native to Europe.

Other info. - This weedy species was reported by Steyermark in just one county but it has since spread into much of the state. The plant can be identified by its bulbosus base and slightly thickened roots. The divided leaves and reflexed sepals are also good characteristics to help with a proper ID.
This is a variable plant in the amount of pubescence of the stem and leaves.

Photographs taken in Brown Summit, NC., 4-20-03.


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