BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Castilleja sessiliflora | Downy Paintbrush 



GENERAL BOTANICAL CHARACTERISTICS : 
Downy paintbrush is a native, hemiparasitic, perennial forb [1,14].  It
has one to several leafy, simple stems from 3.5 to 14 inches (9-35 cm)
tall.  It is ducumbent at the base, and has a woody root crown [14].
The fruit is a capsule [1,14].  Castilleja species have an average root
depth of 11 inches (28 cm), with a range of 10 to 12 inches (25-30 cm)
[8].  In Wisconsin, downy paintbrush is obligately hemiparastic on
eastern redcedar (Juniperus virginiana) and oldfield juniper (J.
communis var.  depressa) [33].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Downy paintbrush regenerates vegetatively by sprouting each year from
the root crown.  It also regenerates sexually.  In Wisconsin,
pollination was accomplished exclusively by bumblebee queens of one
species (Bombus fervidus).  Morphology of the flowers excluded all other
insects [33].  Greens and Curtis [15] reported a seed germination rate
increase from 0 percent to 3 percent with 2 months of cold
stratification in a greenhouse.  Seeds were not scarified or otherwise
treated.


SITE CHARACTERISTICS : 
Downy paintbrush grows throughout its range on dry plains and hills
[11,14,17]. Its elevational range is as follows [3,23,29,33]:

     State             Elevation (feet)     Elevation (m)

  Arizona                3,960-5,610         1,200-1,700
  North Dakota              1,740                527
  South Dakota           3,620-5,030         1,097-1,524
  Wisconsin                  900                 273 

In Missouri and Nebraska downy paintbrush occurs on dry, wind-deposited,
fine sandy-loam soils [16,18].

In North Dakota, South Dakota, and Nebraska, downy paintbrush occurs in
a dry-continental climate with hot summers.  More than half the annual
precipitation occurs during summer months, but uneven annual amount and
distribution, as well as drought, are common [3,12,18,29].  In Arizona,
more than half the scant precipitation occurs from July to October [23].

In Arizona, Nebraska, and Wisconsin, downy paintbrush occurs on soils
with limestone substrate [18,23,33].


SUCCESSIONAL STATUS : 
NO-ENTRY


SEASONAL DEVELOPMENT : 
In central North Dakota temperature appears to be more important than
precipitation in influencing the phenology of downy paintbrush.  Over a
6-year period, the earliest yearly first bloom varied from May 18 to
June 13.  The median date of full flowering was June 9 [3].  In
southwestern North Dakota the average date of earliest bloom was May 18.
Growth started from the root crown in April, and 8 percent of final
height was achieved in that month.  By the end of May 98 percent of
final height was achieved, with growth ending in June [12,14].  In
southern Wisconsin flowering occurs from early May through mid-June
[33].

Related categories for Species: Castilleja sessiliflora | Downy Paintbrush