littleleaf buttercup (Ranunculus abortivus)
Ranunculus abortivus ssp. acrolasius (Fern.) Kapoor & A. & D. Löve
Ranunculus abortivus var. acrolasius Fern.
Ranunculus abortivus var. eucyclus Fern.
Ranunculus abortivus var. indivisus Fern.
Ranunculus abortivus var. typicus Fern.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of littleleaf
buttercup is Ranunculus abortivus L. Three varieties of Ranunculus
abortivus are sometimes recognized; however, the Atlas of Virginia
Flora does not make any variety distinctions. There is the very similar
species, Ranunculus micranthus (discussed in next paragraph), that
is difficult to distinguish from Ranunculus abortivus. The botanical
characteristics necessary to differentiate the two species is very time
sensative; for the 2010 field work, final determination was not possible.
It is feasible that both species are present in Sky Meadows State Park.
For the present, Ranunculus abortivus will be assumed; this may change
with subsequent research.
Littleleaf buttercup, often called small-flowered buttercup, is one of
the more common Ranunculus spp.; however, it is often overshadow-
ed by other more conspicious Ranunculus species, such as Ranunculus
bulbosus (bulbous buttercup). The flowers aren't very showy and this
plant is easily overlooked. There are many Ranunculus spp. in the state
and they are often hard to tell apart. While attempting to identify small-
flowered buttercup, look for lower leaves that are orbicular, kidney-
shaped, or deeply 3-lobed with crenate margins, and slender upper leaves
with mostly smooth margins. The foliage is usually hairless, although
there is an uncommon form of this plant that is finely pubescent. Small-
flowered buttercup is very similar in appearance to Ranunculus micranthus
(also called small-flowered buttercup); both have been recorded in Facquier
County. To distinguish Ranunculus abortivus from Ranunculus micranthus,
it is often necessary to examine the naked receptacles of these two species
(the receptacle of the flower is what remains after the carpels, sepals, and
petals are removed). The receptacle of Ranunculus abortivus is pubescent,
while the receptacle of Ranunculus micranthus is hairless. Another differ-
ence is the following: the achenes of Ranunculus abortivus have a shiny
surface, while the achenes of Ranunculus micranthus have a dull surface.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This native plant is a biennial or short-lived perennial up to 2' tall
that branches occasionally. The green stems are glabrous.
Leaves: The blades of the basal leaves are up to 2" long and 2½" across;
they are orbicular-reniform and crenate along the margins. Their petioles
are up to 3" long. The lower cauline leaves are up to 2" long and across on
petioles up to 1" long; they are often deeply divided into 3 rounded lobes
nd their margins are crenate. The upper cauline leaves are usually lanceo-
late, oblanceolate, or oblong with smooth margins; sometimes they are
shallowly lobed with teeth that are crenate or dentate. The blades of the
upper cauline leaves are up to 1½" long and they are sessile. All of these
leaves are hairless; the cauline leaves alternate along the stems.
Flowers: Each upper stem terminates in 1-3 flowers on individual stalks.
Each flower is about ¼" across, consisting of 5 yellow petals, 5 green
sepals, a cluster of green carpels, and a ring of stamens with bright yellow
anthers. The petals are broadly lanceolate or triangular; they are smaller
than the sepals. The sepals become membranous with age and they fall
off the flower at about the same time as the petals.
Fruit/Seeds: The cluster of carpels (immature achenes) elongates to about
¼" in length and becomes ovoid in shape. The small achenes are somewhat flattened and orbicular in shape; their surfaces are shiny when mature and
they have very small beaks.
Roots: The root system consists of a tuft of fibrous roots.
REGENERATION PROCESS: This plant spreads by reseeding itself.
HABITAT TYPES: Habitats include open woodlands, woodland bor-
ders, areas along woodland paths, degraded meadows, banks of rivers
and ditches, pastures and abandoned fields, edges of yards, vacant lots,
grassy areas along railroads and roads, and waste areas. This plant is
typically found in disturbed areas and is somewhat weedy.
SITE CHARACTERISTICS: This plant is typically found in partial
sunlight, moist to mesic conditions, and a reasonably fertile loam or
clay-loam soil. It has few problems with pests and disease.
SEASONAL DEVELOPMENT: The blooming period occurs from
mid-spring to early summer and lasts about 1-2 months.
GENERAL DISTRIBUTION: Littleleaf buttercup is found throughout
the contential United States and Canada, with the exception of California,
Oregon, Arizona, Nevada, and Utah, and the far northern Canadian terri-
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Ladybird beetles, small bees, syrphid
flies, and other kinds of flies suck nectar from the flowers. Some flies
and ladybird beetles feed on the pollen, while some bees collect pollen
for their larvae. Ants suck nectar that adheres to the carpels after the
petals and sepals fall of the flowers. The wood duck and wild turkey
eat the foliage and seeds of Ranunculus spp. (Buttercups). Some small
rodents, including the eastern chipmunk and meadow vole, eat the seeds,
while the cottontail rabbit eats the foliage. However, the use of the foli-
age and seeds as a food source by these animals is rather limited. The
foliage contains a blistering agent and is mildly toxic to livestock.
Crooked Run Valley