BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Taraxacum officinale | Dandelion 



GENERAL BOTANICAL CHARACTERISTICS : 
Dandelion is an introduced, cool-season, perennial forb [140].  It has a
thick taproot up to 6 inches (15.2 cm) long [135].  Stems are very short
and wholly underground, producing a rosette of leaves at the ground
surface.  Leaves are 2 to 16 inches (5-40 cm) long [134].  The flower
heads are solitary at the end of naked, hollow stalks.  Stalks can reach
heights up to 2 feet (60 cm) [126,135].  One head contains from 100 to
300 flowers [126].  Seeds of dandelion are topped by a parachute of
bristles that aid in dissemination [55].

Dandelion forms vesicular-arbuscular mycorrhizal associations
[15,37].
    


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Dandelion reproduces apomictically through parthenogenesis [62].  Plants
develop from unfertilized gametes.  Dandelion is an aggressive seed
producer and reproduces mainly from seed [42].  Seeds travel a
considerable distance because of the parachuting effect produced by the
spreading pappus.  In a tallgrass pairie in Iowa, achenes of dandelion
were blown by the wind several hundred meters from the nearest source
population [98].

Dandelion creates a long-lived seedbank [11,99].  In a seedbank of a
ponderosa pine community in Washington, viable dandelion seedlings
emerged from litter and soil samples in greenhouse germination trials.
Seed density of spring samples was 160 seeds per square yard (133
seeds/m sq) and of autumn samples was 60 seeds per square yard (50
seeds/m sq) [99].  Seeds of dandelion were viable up to 5 years in soil
samples from Montana [11].  Seed germination on a control plot in
Wisconsin was inhibited by thick mulch.  Light mulch that remained on a
mowed plot also reduced germination [36].  Germination was highest on a
burned plot [36].

Vegetative:  Dandelion sprouts from the caudex after disturbance
[114,126].


SITE CHARACTERISTICS : 
Dandelion tolerates a wide range of site and soil conditions, but it
most commonly occurs in disturbed areas such as cut-over or burned
forests, avalanche areas, overgrazed ranges, and marshy floodplains
[54,133].  It also occurs sites on highway and railroad rights-of-way,
waste places, old fields, pastures, and lawns [114,126].

Dandelion occurs on soils that vary from thin layers above permafrost in
the subarctic to deep loams in the western United States [37,114].  Soil
texture ranges from clays and clayey loams to sandy loams.  Dandelion
does poorly on dense clay soils, saline soils, and acidic soils [37].

Dandelion occurs on flat to rolling topography or moderate to steep
slopes [27,37].  It is found from sea level to high alpine elevations
[126].  Regional elevational distributions are as follows [27,37,99]:

                                 feet                 meters

Utah                         4,100-11,300           1,250-3,445
Colorado                     4,500-13,500           1,372-4,115
Wyoming                      4,100- 9,600           1,250-2,926
Montana                      2,900- 9,200             884-2,804
Washington                   2,574- 2,722             780-825
Oregon                       7,095- 7,920           2,150-2,400
Alberta                      4,323- 6,336           1,310-1,920

Common shrubs, grasses, and forbs associated with dandelion include
common snowberry (Symphoricarpos albus), Wood's rose (Rosa woodsii),
russet buffalo berry (Sheperdia canadensis), blueberry (Vaccinium spp.),
chokecherry (Prunus virginiana), black sagebrush (Artemesia arbuscula
nova), Wyoming big sagebrush (A. tridentata ssp. wyomingensis),
Oregon-grape (Manonia repens), rough fescue (Festuca scabrella), Idaho
fescue (F. idahoensis), slender wheatgrass (Elymus trachycaulus),
prairie junegrass (Koeleria cristata), timber danthonia (Danthonia
intermedia), Richardson's needlegrass (Stipa richardsonii), timothy
(Phleum pratense), tufted hairgrass (Deschampsia caespitosa), Kentucky
bluegrass (Poa pratensis), aster (Aster spp.), willowweed (Epilobium
spp.), prairiesmoke avens (Geum triflorum), small-leaf angelica
(Angelica pinnata), Colorado columbine (Aquilegia caerula),
rhexia-leaved paintbrush (Castilleja leonardii), Oregon fleabane
(Erigeron speciousus), wallflower (Erysimum elatum), one-flower
helianthella (Helianthella uniflora), Utah peavine (Lathyrus utahensis),
and Richardson geranium (Geranium richardsonii) [32,83,117,124,129].
  


SUCCESSIONAL STATUS : 
Obligate Initial Community Species

Dandelion is an important colonizer following vegetation disturbances in
temperate climates throughout North America [85,99].  Although the role
of dandelion as an early seral species does not change, the length of
time dandelion populations are present varies among ecosystems.
Dandelion enters a disturbed community and rapidly becomes abundant.  It
may achieve a peak in dominance within 2 to 3 years [7,14].  Holland
found dandelion to be a transitory colonist of marsh habitats in
Massachusetts; it was found for 10 years after the disturbance and then
disappeared [53].

Dandelion was one of the earliest colonizers after tree havesting in a
maple-beech-birch ecosystem in Michigan [32].  On an abandoned farmland
in Arizona, dandelion was one of the predominant species following
winter precipitation [30].  Dandelion was a pioneer species on a
brine-killed forest site after elimination of brine discharge on the
site in the spring of 1982 [7].  On a Douglas-fir clearcut in Colorado,
dandelion was a dominant species in the understory the second year after
cutting but was not present in the initial community [7].  Dandelion is
not a member of the climax plant community on rangelands since it cannot
withstand competition for moisture, nutrients, and light with the climax
vegetation.  It invades these areas after the preferred species have
been removed by overgrazing [85].


SEASONAL DEVELOPMENT : 
Dandelion is one of the earliest spring bloomers on western rangelands
[134].  It flowers from March to late fall in most states and will
flower throughout the year in warmer areas [126].  General first
flowering dates are from April 28 to May 19, and sometimes earlier in
some locations [116].  By mid-June, dandelion has reached its maximum
bloom stage, and the seeds from earlier flowering dates are mostly
disseminated.  By mid-July, all seeds are disseminated [40].

Reported dates for anthesis in some states are as follows [16,37,100]:

Utah                             April-July
Colorado                         April-August
Wyoming                          May-August
Montana                          April-September
North Dakota                     April-June
Virginia                         February-June
Georgia                          February-June
Mississippi                      February-June
Tennessee                        February-June
Kentucky                         February-June
Iowa                             April-June
Alberta                          June-July

Related categories for Species: Taraxacum officinale | Dandelion