Corn Buttercup

This annual plant flowers from May to July (5). It is visited by small flies (2).

Very little direct conservation action has been targeted at this species. It may benefit from agri-environment schemes.

Corn buttercup produces yellow flowers with shiny petals on an erect, leafy stem (2). The leaves are split into narrow lobes (5), and the seed heads (called achenes) are extremely spiky (3), and have earned this buttercup the alternative local names of Devil's claws, Devil-on-all-sides, and hellweed (4).

This species is a weed of cornfields (3), and seems to prefer calcareous soils (2) and clay (6). It also occasionally occurs on disturbed ground, such as on road-sides (2).

Formerly widespread, but now very scarce (3) and only seen regularly in the south of England (5). It also occurs at a few sites in Wales, south-west England and some scattered localities in the north-west of England and Scotland (2). Elsewhere it is found in central and southern Europe, North Africa and west Asia, reaching as far east as India (2).

No conservation designations.

It is likely that agricultural intensification is responsible for the decline of this once common species (4), starting at the end of the nineteenth century when seed cleaning techniques were improved (2). Like all weeds of arable land, corn buttercup faces the more modern threats of herbicide and fertiliser use, the loss of field-margins, the use of more productive and competitive crops and alterations in the traditional style of crop rotation (4).

Mediterranean region.

Europe, Mediterranean region, West Asia to India.

Herbs annual. Stems ca. 30 cm, sparsely appressed puberulent, branched. Basal leaves 3--5; petiole 1.6--6 cm, sparsely puberulent; blade 3-lobed, 3-partite, or 3-sect, obovate or broadly rhombic, 1.5--3.5 × 1.5--4 cm, papery, sparsely appressed puberulent, base cuneate or broadly cuneate, lobes narrowly cuneate, 2- or 3-dentate at apex. Stem leaves petiolate or sessile, 1- or 2-ternate, ultimate lobes narrowly cuneate or linear-lanceolate. Flowers leaf-opposed, ca. 1 cm in diam. Pedicel 2--4 cm, appressed puberulent. Receptacle puberulent. Sepals 5, narrowly ovate, ca. 5 mm, abaxially appressed puberulent. Petals 5, obovate, ca. 5 × 3.8 mm, nectary pit covered by a scale, apex rounded. Stamens numerous. Aggregate fruit subglobose, ca. 1.2 cm in diam. Achene complanate, elliptic, ca. 5 × 3.5 mm, glabrous, spiny, spines up to 2 mm; style persistent, ca. 2.6 mm. Fl. Apr--May.

Stems erect or ascending, sparsely pilose. Basal and lower cauline leaf blades obovate to rhombic in outline, 3-parted or 3(-5)-foliolate, 1.8-5.2 × 1.6-4.2 cm, leaflets oblanceolate or divided into oblanceolate or linear segments, leaflet base narrowly acuminate, margins entire or distally dentate, apex rounded or acuminate. Flowers pedicellate; receptacle sparsely hispid; sepals 5, spreading, 4-7 × 1-2 mm, strigose; petals 5, 5-8 × 2-4 mm. Heads of achenes discoid, 8-9 mm across; achenes 5-8 per head, 4-6.4 × 2.8-4.4 mm, faces and margin covered with long spines, glabrous; beak lance-subulate, straight, 1.6-3.8 mm.

introduced; Ark., Calif., D.C., Ga., Idaho, Ill., Kans., La., Miss., Mo., N.J., N.Y., N.C., Oreg., Pa., S.C., Tenn., Utah, Wash.; South America; native to Eurasia; Pacific Islands; Australia.

Flowering spring (Mar-Jun).

Grasslands, ephemeral pools, disturbed areas; 0-1200m.

Naturalized in sandy places along roads. Anhui, Hubei [native to W Asia and Europe].

Ranunculus arvensis var. tuberculatus de Candolle

Ranunculus arvensis, the corn buttercup or field buttercup, is a plant species in the family Ranunculaceae. Native to Europe, it can be found on other continents as an introduced species and sometimes a weed, including in North America and Australia. It was formerly a common annual arable weed in Britain, but is now rare there. It is most often found in moist places, such as spring puddles in meadows.

Many local common names refer to the spines on the seed heads or the achenes on the mature fruit:

devil's claws hellweed devil-on-both-sides devil's coach wheel devil's currycombs crowclaws (Yorkshire) horse-gold (Yorkshire) eggs-and-bacon (Cheshire) jackweed (Oxfordshire)