Description: This adventive perennial plant is
1½–2½' tall, branching frequently in the upper third of the
plant. It is erect, rather than sprawling or stoloniferous. The stems are round
and covered with long white
hairs. The alternate leaves are palmately compound.
The lower leaves have long hairy petioles and 5-7 leaflets, while the upper
leaves are nearly sessile, smaller in size, and often have 3 leaflets. Each
leaflet is up to 3½" long and ¾" across; the middle leaflets are
larger in size than the side leaflets. Each leaflet is oblanceolate and
coarsely toothed. The upper stems terminate in small clusters of flowers that
are held at approximately the same distance from the ground; as a consequence,
the upper part of the plant is spreading, but rather flattened on top. Each
flower is about ¾" across, consisting of 5 pale yellow petals, 5 hairy
green sepals, 30 stamens with brown-yellow anthers, and a bright yellow
receptacle in the middle with numerous pistils. The spreading petals are
obcordate, while the triangular sepals are a little shorter than the petals.
The blooming period usually occurs from early to mid-summer and lasts about a
month. Each flower produces numerous dark brown seeds, which are somewhat
flattened and finely ridged. The root system of mature plants consists of a
shallow caudex with coarse secondary roots; sometimes multiple stems develop
from this caudex. Young plants have a branching taproot. Reproduction is by
seeds.
Cultivation: The preference
is full sun, mesic to dry conditions, and a somewhat heavy soil containing clay
or gravel. This plant is quite tolerant of alkaline soil.
Range
& Habitat: Sulfur Cinquefoil is a common plant that occurs in
most counties of Illinois (see
Distribution
Map). It is adventive from Eurasia. Habitats include limestone glades,
pastures and abandoned fields, vacant lots, gravelly areas along railroads,
compacted soil along grassy paths or dirt roads, and weedy meadows. This plant
prefers disturbed areas with limey soil.
Faunal Associations: The nectar and pollen of the
flowers attract small bees and flies. Rabbits occasionally eat the lower leaves
of this plant, but it is not a preferred food source. Livestock also eat this
and other Potentilla spp. (Cinquefoils). There is some evidence that the
seeds of Cinquefoils can pass through the digestive tract of livestock and
remain viable. Thus, these animals may facilitate their distribution into new
areas.
Photographic Location: A
railroad overpass containing shallow gravelly soil along the tracks in Urbana,
Illinois.
Comments: Sulfur
Cinquefoil has reasonably attractive flowers and foliage. The latter has some
resemblance to the foliage of Cannabis sativa (Marijuana). However,
Marijuana is usually a taller plant with very different flowers. Its leaflets
are narrowly ovate and longer than the leaflets of Sulfur Cinquefoil. There are
many kinds of Cinquefoils, both native and introduced, that are often hard to
tell apart. Sulfur Cinquefoil can be distinguished by its erect habit, palmate
leaves with 5 or 7 leaflets, pale yellow petals that are longer than the
sepals, and terminal clusters of flowers. Other species of Cinquefoils have
stems that are sprawling or stoloniferous, palmate leaves with only 3 leaflets,
bright yellow petals that are no longer or shorter than the sepals, or flowers
that develop individually from the leaf axils.