BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Wyethia amplexicaulis | Mules Ears 



GENERAL BOTANICAL CHARACTERISTICS : 
Mules ears is a native, perennial, cool-season forb with stems up to 32
inches (80 cm) tall.  The leaves are alternate and are 8 to 16 inches
(20-40 cm) long and 2 to 6 inches (5-15 cm) wide.  There are usually
several flower heads but flower heads may occasionally be solitary.  The
fruits are achenes [12,16,32].  Mules ears has a stout taproot up to 9
inches (22 cm) in circumference.  The taproot may reach depths of over 6
feet (180 cm).  Strong lateral roots run 3 to 4 feet (90-120 cm) from
the main root [31].  Mules ears is strongly aromatic [1,19].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte
   Geophyte


REGENERATION PROCESSES : 
Mules ears reproduces by seed [19,26,30,35].  Seeds germinate without
stratification, but a cool-moist stratification greatly enhances
germination.  Best germination occurs when seeds are stratified for 4
weeks at 35 to 41 degrees Fahrenheit (2-5 deg C) [35].

Mules ears sprouts from underground rootstalks or from the root crown
following damage to aboveground portions of the plant [20,37].


SITE CHARACTERISTICS : 
Mules ears is found in moist draws, meadows, open woods, and open
grasslands [12,13,19,26].  Elevational limits of mules ears are from
4,500 to 11,000 feet (1,360-3,300 m) [8].  Mules ears requires 10 to 18
inches (25.4-45.7 cm) of annual precipitation [19].  It grows well on
sandy loam, loam, and clay-loam textured soils [8], but is apparently
most aggressive in heavy clay soils [11,18].  Mules ears grows well on
gentle to moderately steep slopes [8].

The trembling aspen/mules ears community types of the Bridger-Teton,
Caribou, and Targhee National Forests are usually found below 7,000 feet
(2,120 m).  They most often occur in heavy clay soils with slopes seldom
exceeding 25 percent [17,18,37].

Mules ears-dominated subalpine forb communities also occur in heavy clay
soils on the Bridger-Teton National Forest.  The forb communities are
characterized by large stands of mules ears surrounded by trembling
aspen or subalpine fir (Abies lasiocarpa).  They are found at the lower
elevations of the subalpine zone (average elevation 7,296 feet [2,210
m]).  Average soil pH of these stands is 6.4 [11].
  


SUCCESSIONAL STATUS : 
Facultative Seral Species

Mules ears is highly competitive and aggressive and often occurs in
large, dense, almost pure stands [26,28,30].  Its aggression on some
sites may be partly attributed to its ability to dominate heavy clay
soils [28] and its tendency to monopolize soil moisture [19,37].  It
excludes other species in some heavily grazed areas [11,17,35].  Even
when grazing pressure is eliminated, mules ears persists for a long time
[22].

Mules ears is common in seral coniferous forests within its range [35].


SEASONAL DEVELOPMENT : 
Mules ears begins growth in March or April and flowers from April until
June [26].  Annual growth usually dries up by July [31].

Related categories for Species: Wyethia amplexicaulis | Mules Ears