Old Field Cinquefoil (Potentilla simplex*) of the Rose (Rosaceae) family is a low-growing plant with short rhizomes and 5-petal, bright yellow flowers. The genus name is from the Latin word for “powerful” in reference to medicinal properties of some species of the genus. The specific epithet is Latin for “simple” in reference to the plant’s typically unbranched stems. “Cinquefoil” is French for “five leaves” in reference to the five (sometimes 7) leaflets. In the U.S., it occurs in an area bounded by a line from eastern Oklahoma into Minnesota, across to Maine, thence south along the Atlantic Coast to South Carolina, thence southwest to south Alabama and west to northeast Texas. It also extends into eastern Canada. In Arkansas, occurrence is statewide. It is also known as Five-Finger Cinquefoil and Common Cinquefoil. Habitats include moist to dry sunny sites with various well-drained soils of woodland edges, prairies, rights-of way, disturbed areas and abandoned fields.
Old Field Cinquefoil has palmate basal leaves tightly clustered around a stem. Nodes along stems produce palmate cauline leaves, leafy bracts and flowers. Early in their growth, stems are erect and green, becoming reddish with age. The string-like to cord-like ascending to prostrate stems, to 3+ feet long, have well-spaced nodes. Stems, typically not branched, have node-to-node segments from less than 1 inch to 6+ inches. Stem segments between the lowermost nodes are straight, while stem-segments along mid-stem are broadly arched and the most distal segments are straight. The distal trailing portion of stems is stoloniferous, with stem-tips that root to form clonal plantlets. At the end of their first growth year, new rhizomes are bulbous and smooth with irregular growth rings. Dead stems remain attached to new rhizomes for a year or so.
The shallow, horizontal rhizomes are segmented by growth-years with new growth elongating rhizomes from their distal tips. One to several new growth points may develop along the sides so that the original rhizomes may become branched so that a plant may have several growing tips. With each growing tip bearing several stems, in a favorable habitat, a dense mat of clonal plants may form. Stems bear palmate leaves (cauline leaves) and flowers at their proximal nodes, along with leafy bracts, while more distal nodes bear only leafy bracts. Bracts, to 1 inch long, have one to several lanceolate lobes which may be entire or divided. Diameter of stems and size of leaves and bracts gradually decrease toward the stems’ apices. The cauline leaves have broadened bases similar to those of basal leaves (see below).
Each growth year, a new segment is added to the distal end of rhizomes. This growth pattern results in rhizomes being segmented and roughened by remnants of leaf and stem bases (the first segment being smooth). Each growth year, long fibrous roots grow from the underside of the most recent rhizome segment. When a rhizome reaches its third to fourth year, the older segments begin to decay so that the viable portion of rhizomes is limited to several inches. The tough rhizomes (about ¼ inch in diameter) have a dense, white interior with a pinkish hue.
New basal leaves, appearing overwinter, encircle the growing tips of rhizomes. In spring, as rhizome growth continues, additional basal palmate leaves develop (as earlier leaves die) and long stems appear, also bearing palmate leaves. Basal leaves have 5 (sometimes 7) sessile leaflets while cauline leaves have 5-3 sessile leaflets. Leaflets of cauline leaves tend to be larger and more elongate. Leaflets of basal leaves tend to be obovate (with broadly rounded apices) while those of cauline leaves tend to be more elongate (with broadly tapered apices). All leaflets have wedge-shaped bases. Petioles are initially the same color as lower sides of leaves but become reddish over time. Petioles often have dense appressed pubescence. Bases of petioles, tightly pressed together in a flattened group, have V-shaped “wings” in cross-section (to ⅝ inch long) as a result of having clasped additional emerging leaves and encircled stems. The wings, often hidden in the litter layer, have free-standing, lanceolate apices with straight side-margins.
Basal and cauline palmate leaves are similar. Leaflets, narrowly obovate to broadly lanceolate, have a glossy green upper surface and a pale to silvery green lower surface. Central leaflets are largest, usually 2 or more times as long as wide, and the lower lateral pair is smallest. Leaves may have an “extra” small pair of lateral leaflets (for 7 leaflets) or may have only 3 leaflets. Upper one-half to three-fourths of a leaflet’s margins have 4 to 10 prominent teeth per side. Pinnate venation is finely depressed on the upper surface and finely expressed on the lower surface. Secondary veins terminate at the mucronate tips of the marginal teeth. The midvein terminates leaflets with a smaller tooth. Leaflets are symmetrical across the midvein except lateral leaflets have down-trending midveins. Leaf pubescence is variable in that either surface may be somewhat hairy to glabrous and the petiole, too, has variable pubescence. The pale green petioles, to 6 inches long, become reddish with age. Cauline leaves may be sessile.
The blooming period begins in the early weeks of spring and continues for about a month. The inflorescence consist of a few single flowers per stem on long, very slender pedicels (to 3 inches long). There is one flower per palmate-leaf-bearing node. The lowermost flower is typically at the node with the second lowest cauline leaf.
The yellow flowers (to ½ inch wide) have 5 petals, about 20 stamens (filaments + anthers) and 20-50 pistils (ovary + style + stigma); all the same bright yellow. The obovate petals have rounded apices with a shallow apical indention (retuse petals) and a clawed base. Stamens are in a single row encircling a short-elongate receptacle covered with straight, slender and terete styles/stigmas. The styles/stigmas flex from the receptacle in rather random fashion.
Flowers have a calyx of 5 broad-triangular sepals immediately above an epicalyx of 5 triangular-lanceolate floral bracts. Sepals and bracts extend straight-out from the pedicel. Sepals are positioned between the petals and bracts. The dark green, pubescent sepals are broadly triangular with short-acute apices while bracts are broadly lanceolate with acuminate apices. Sepals are shorter than bracts and bracts are about the same length as petals. The elongate anthers, with widened bases, stand upright on tips of filaments. Styles are tipped with tiny, poorly defined stigmas.
With maturity of fruiting heads, styles/stigmas drop off the receptacle while drying stamens persist as receptacle, sepals, bracts and pedicels remain green. Heads bear an aggregate of one-seeded indehiscent nutlets. The glabrous bean-shaped nutlets, about 1/32-inch long, are tan with a roughened surface. The seeds’ small size and weak attachment suggest that nutlets could be dispersed by strong wind and fallen nutlets could be transported by surface-water flow during heavy rains.
Regarding garden use, Old Field Cinquefoil has pleasing visual characteristics (palmate leaves, bright flowers). Flowers provide pollen and nectar for insects and foliage for deer, rabbits and marmots. With its stoloniferous stems, extending as far as 3 feet, it could expand quickly. Should be welcomed in natural areas. May provide a good groundcover to stabilize soil from erosion. Degree of self-seeding is not known.
Three additional species in the genus occur in Arkansas; namely, Dwarf or Five-Finger Cinquefoil** (Potentilla canadensis), Rough Cinquefoil (Potentilla norvegica) and Sulfur or Rough-Fruit Cinquefoil (Potentilla recta). Also, Mock or Indian-Strawberry (Duchesnea indica) is sometimes treated within the genus (as Potentilla indica). Of these species, Dwarf Cinquefoil is most similar. Dwarf Cinquefoil is a smaller plant with smaller and strongly obovate to oblanceolate leaflets, with fewer teeth. Flowers of Dwarf Cinquefoil usually occur from the first stem node and thinner stems are usually prostrate from the start of growth. Dwarf Cinquefoil has been reported from northeastern Arkansas.
*This species has considerable variation in leaf and stem pubescence, to the extent that some authorities have named three varieties. Other authorities (including Arkansas) treat these varieties as a continuum within the species.
**The common name “Five-Finger” is used for both P. simplex and P. canadensis.
Article and photographs by ANPS member Sid Vogelpohl