BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix planifolia ssp. planifolia | Planeleaf Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Planeleaf willow is a small-to medium-sized deciduous shrub.  Variety
monica is small, usually less than 3.3 feet (1 m) tall, and has erect or
decumbent stems [7].  In Yellowstone National Park, it seldom exceeds 17
inches (45 cm) in height, and is often obscured by tall and dense sedges
[30].  Variety planifolia is larger, growing up to 13 feet (4 m) in
height.  It has numerous, stout, upright stems arising from a basal
cluster [15,42].

Planeleaf willow bark is gray and smooth [43].  The flowers occur in
about 1- to 2-inch-long (2.5 cm), erect catkins on the previous year's
twigs [3].


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (nanophanerophyte)
   Burned or Clipped State:  Hemicryptophyte


REGENERATION PROCESSES : 
Planeleaf willow's primary mode of reproduction is sexual.  It produces
an abundance of small, light-weight seeds.  Like most willows, it
probably begins seed production at an early age (between 2 and 10 years)
[23].  At maturity, the fruit splits open and releases the seed.  Each
seed has a cottony down that aids in dispersal by wind and water [6].
Seeds are dispersed during the growing season and remain viable for only
about 1 week [6].  The seeds contain significant amounts of chlorophyll,
and photosynthesis generally occurs as soon as the seed is moistened.
Germination occurs within 24 hours of dispersal if a moist seedbed is
reached [6].  Exposed mineral soils provide the best seedbed [23].
Litter inhibits germination [23].

Vegetative reproduction:  Planeleaf willow sprouts from the root crown
or stem base if aboveground stems are broken or destroyed by cutting,
flooding, or fire [23].  Detached stem fragments form adventitious roots
if they remain moist; portions of stems will root naturally if buried in
moist soil [23].


SITE CHARACTERISTICS : 
The two varieties of planeleaf willow occupy different habitats.
Variety monica, the high elevation variety, grows in middle and upper
subalpine zones dominated by Engelmann spruce (Picea engelmannii),
subalpine fir (Abies lasiocarpa), and lodgepole pine (Pinus contorta)
and in alpine zones above timberline.  It commonly forms thickets along
stream and lake margins, in wet meadows and seep areas, and on slopes
kept moist by melting snow [2,7,22,30].  These sites are usually wet,
with water tables at or near the surface [7,34].  Soils may be mineral
or organic.  Mineral soils are clayey-, silty-, or sandy-textured and
overlain by a shallow, organic surface layer [7].  On marshy sites peat
may be up to 12 inches (30 cm) or more thick [22,30].  Associates
include Wolff willow (Salix wolfii), undergreen willow (S. commutata),
Drummond willow (S. drummondiana), grayleaf willow (S. glauca), bog
birch (Betula glandulosa), water sedge (Carex aquatilis), beaked sedge
(C. rostrata), mountain sedge (C. scopulorum), tufted hairgrass
(Deschampsia cespitosa), bluejoint reedgrass (Calamagrostis canadensis),
marshmarigold (Caltha leptosepala), heartleaf bittercress (Cardamine
cordifolia), and arrowleaf groundsel (Senecio triangularis)
[22,28,30,34].

Variety planifolia grows at middle elevations in the West, primarily in
the Douglas-fir (Pseudotsuga menziesii) and sagebrush (Artemisia spp.)
zones [7].  It generally occurs scattered in other willow-dominated
communities along the banks of streams, ponds, and lakes and in wet
meadows and marshes.  Associated willows in the West include Geyer
willow (S. geyeriana), Drummond willow, and Bebb willow (S. bebbiana)
[7].  Soils are usually mineral, with textures varying from sands to
clays [18].  Water tables are often near the surface in the spring, but
may drop to more than 39 inches (1 m) by midsummer [18].  In Ontario,
this variety grows in cool, moist habitats along lakes and streams, in
black spruce (Picea mariana) bogs, northern white-cedar (Thuja
occidentalis) swamps, and marshes [42].

Elevational ranges for several western states are presented below
[7,9,15,21,33,49]:

State                  Elevational Range       

CA          from 8,000 to 12,500 feet (2,440-3,811 m)
CO          from 8,000 to 13,000 feet (2,440-3,963 m) (var. monica)
c ID        above 8,000 feet (2,440 m)  (var. monica)
c ID        from 5,500 to 7,700 feet (1,677-2,348 m) (var. planifolia)
MT          from 3,700 to 10,200 feet (1,128-3,109 m) 
SD, Black   from 5,000 to 6,500 feet (1,524-1,982 m)
 Hills                      
UT          from 7,400 to 12,000 feet (2,255-3,660 m)
WY          from 6,500 to 11,500 feet (1,982-3,506 m)


SUCCESSIONAL STATUS : 
Variety monica often forms relatively stable communities maintained by
high water tables and high elevation climates [22,34].  In Colorado,
high elevation planeleaf willow communities are considered climax
wetland communities [22].  These communities can experience successional
shifts if water tables change.  If sites become permanently drier, Wolff
willow and grasses will increase [18].  Variety planifolia often
persists in communities dominated by other willows.  These communities
are relatively stable and maintained by high water tables or seasonal
flooding [34].  Both varieties are shade intolerant.


SEASONAL DEVELOPMENT : 
Planeleaf willow flowers appear in the spring before or sometimes with
the leaves [2,43].  Flowering and seed maturation dates are as follows:

Location                 Flowering        Seeds mature       Reference 

California             June to August                          [33]
New England
(low elevations)       May 19-June 27
(high elevations)      July 9-July 31                          [41]
Ontario                 May and June      June and July        [42]
North & South Dakota       May               June              [44] 

Related categories for Species: Salix planifolia ssp. planifolia | Planeleaf Willow