Ranunculus parviflorus L. - Small-flowered Buttercup

Ranunculus parviflorus plant

Family - Ranunculaceae

Stems - From fibrous roots, multiple from the base, branching, terete, densely pilose to villous, herbaceous, to +/-15cm tall, erect to ascending.

Ranunculus parviflorus stemStem.

Leaves - Alternate, petiolate. Petiole sheathing at the base, to +/-10cm long, pubescent as the stem, with a thin and shallow adaxial groove. Blades 3-5 palmately lobed, 3-4cm broad and long, sparse villous above and below. Lobes dentate, the teeth often with minute whitish tips.

Ranunculus parviflorus leaves

Inflorescence - Single axillary flower from the base of the newest leaves, flowers hidden by the larger leaves of the plant. Flowers sessile at first but quickly becoming pedunculate. Peduncle to +/-2.5cm in fruit, villous, erect.

Flowers - Petals absent or reduced, spatulate, yellow, glabrous, to 2mm long, 1mm broad, rounded at the apex. Stamens +/-10, erect, from the base of the carpels, clavate. Anthers yellow, -1mm long. Receptacle naked. Carpels compressed, antrorse puberulent in the center. Sepals yellowish, reflexed, villous abaxially, glabrous adaxially, to 2mm long, +1mm broad, acute, lanceolate to ovate. Achenes to 3.5mm long, 2mm broad, pale green but with darker green margins near the apex, with a short beak to .5mm long. Beak straight or slightly curved.

Ranunculus parviflorus flowerFlower.

Ranunculus parviflorus fruitsFruits.

Flowering - March - June.

Habitat - Open ground, waste ground, rocky pastures, dry soils, roadsides.

Origin - Native to Europe.

Other info. - This little introduced species can be found in a handful of Missouri counties. It is likely that the plant will spread with time as it grows well in disturbed areas.
R. parviflorus is an easy plant to identify in the field because of its minute flowers (parviflorus in Latin) and hairy stems.
Another species, R. plattensis, is similar but has sessile flowers and fruits. R. plattensis is not found in Missouri.

Photographs taken in Brown Summit, NC., 4-12-03, and off Lee Rd 54, Auburn, AL., 5-14-05.


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