Description: This native perennial plant consists of
a loose rosette of basal leaves up to 1' across. Each basal leaf is about 6"
long and ¼" across, although occasionally a larger size is achieved. The
basal leaves
are semi-erect, linear in shape, and
various shades of green, depending on the local ecotype. They are smooth,
finely crisped, and often downy white along the margins. There is a prominent
central vein along the length of each basal leaf. From the center of each
rosette, there develops one or more leafless stalks about 6-8" tall. Each stalk
terminates in a single yellow to golden yellow flowerhead that is about 1-2"
across. The basal leaves and flowering stalks are glabrous or slightly
pubescent, and they contain a milky latex. Each flowerhead consists of numerous
spreading ray florets that are yellow or golden yellow and no disk florets.
Each ray floret is truncated and 5-toothed at its tip. The floral bracts
surrounding the base of each flowerhead are lanceolate and occur in a single
overlapping series. The blooming period occurs from mid- to late spring and
lasts about a month. A single plant may produce several flowerheads in
succession. The achenes are bullet-shaped and have tufts of white hair. They
are distributed by the wind. The root system consists of a stout taproot that
is quite large for the size of the plant. This plant spreads by reseeding
itself.
Cultivation: The preference
is full sun and dry conditions. The soil should be gritty in texture and
well-drained, otherwise crown rot may infect the taproot and the plant will
die. Taller and more aggressive plant species should be prevented from
overcrowding this plant, which normally grows on rocky hilltops and slopes
where there is scant ground vegetation.
Range
& Habitat: Prairie Dandelion is a rare plant that occurs in the
northern half of Illinois, especially in the NW quarter of the state (see
Distribution
Map). It is state-listed as an endangered species. Some local populations
that have been observed in the past are probably extirpated as a result of
habitat destruction. Illinois lies at the eastern limit of its distribution;
the Prairie Dandelion is more common in states further to the west. Habitats
include dry upland areas of prairies, hill prairies, and rocky slopes. This
conservative
species does not normally occur in
disturbed areas.
Faunal
Associations: Little is known about the floral-faunal relationships
of this rare plant. Various kinds of bees (especially bumblebees) are
undoubtedly the most important pollinators of the flowers, where they seek
nectar and pollen. It is possible that rabbits will eat the foliage, although I
have not observed this. Early pioneers ate the roots as a source of emergency
food.
Photographic Location: The
webmaster's wildflower garden in Urbana, Illinois.
Comments: This is one of many species in the Chicory
tribe of the Aster family that have dandelion-like flowerheads and foliage with
a milky latex. The most familiar member of this group is the introduced
Taraxacum officinale (Dandelion), which is a common lawn weed. The
Prairie Dandelion can be distinguished from similar species by considering the
following characteristics: 1) This is a perennial plant, rather than a biennial
or annual, 2) stems with cauline leaves are never produced, 3) there is only
one flowerhead per leafless stalk, 4) the flowerheads are at least 1" across,
5) the basal leaves are linear in shape and they lack teeth or lobes, and 6)
the margins of the leaves are usually finely crisped and/or downy white. Other
members of the Chicory tribe in Illinois usually lack one or more of these
features. The closely related Agoseris spp. (Mountain Dandelions) of the
western states have many of these features, but their achenes are conspicuously
constricted below the apex. The achenes of the Prairie Dandelion are
unconstricted or only slightly constricted below the apex. Other scientific
names are occasionally used to refer to the Prairie Dandelion, including
Agoseris cuspidata and Microseris
cuspidata.