BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Arnica cordifolia | Heartleaf Arnica 



GENERAL BOTANICAL CHARACTERISTICS : 
Heartleaf arnica is a native, perennial herb 6 to 24 inches (15-60 cm)
tall, with upright stems arising singly from long, slender, creeping
rhizomes [18].  Rhizomes grow laterally 0.4 to 0.8 inches (1-2 cm) below
the soil surface [7].  Root depths of 24 inches (60.9 cm) have been
recorded in Montana [35].

The life span of heartleaf arnica is estimated at 12 years [6].




RAUNKIAER LIFE FORM : 
   Geophyte


REGENERATION PROCESSES : 
Sexual:  Heartleaf arnica reproduces by wind-dispersed seed [6,7].  In
central Idaho, Kramer and Johnson [27] found 25 percent of heartleaf
arnica seed was in the upper 2 inches (5 cm) of soil, while 75 percent
was 2 to 5 inches (5-10 cm) below the soil surface.

Asexual:  Heartleaf arnica sprouts from rhizomes [7,24,32].


SITE CHARACTERISTICS : 
Heartleaf arnica occurs in boreal and cool temperate climates.  It is
commonly found in open-canopy coniferous forests on high elevation
water-shedding sites.  It often inhabits exposed, moderately dry mineral
soils, but occurs on a variety of soil types [25].  In California it is
found from 3,500 to 10,000 feet (1,050-3,000 m), in dry to moist open or
wooded places [33].  In Utah it is found from 5,000 to 11,000 feet
(1,525-3,355 m) [44].  Occurrence increases with elevation.  In the
Madison Range of Montana it is the primary ground cover in subalpine fir
(Abies lasiocarpa) forests above 9,000 feet (2,723 m) [36].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Heartleaf arnica is tolerant of both sun and shade, and may be present
from initial to late seres [42,47].  Geier-Hayes found it increased the
first 2 years following logging in a Douglas-fir/white spiraea
(Pseudotsuga mensiesii/Spiraea betulifolia) habitat type in central
Idaho [17].  This was probably due to mass flowering, which occurs 1 to
2 years after disturbance [41].  Heartleaf arnica importance apparently
decreases within a few years after disturbance-induced mass flowering
and increases again in later seres, possibly through vegetative
reproduction.  Steele and Geier-Hayes [46] found it reached highest
coverage in late seral stages of the grand fir/globe huckleberry (Abies
grandis/Vaccinium globulare) habitat type of central Idaho.  It is a
near-climax indicator of that habitat type.


SEASONAL DEVELOPMENT : 
Heartleaf arnica flowers from May through August in California [33] and
May through September in Colorado [13].  In Montana, flowering begins in
early June, fruits ripen in mid-July, and seeds are dispersed at the end
of July [40].

Related categories for Species: Arnica cordifolia | Heartleaf Arnica