BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Amorpha canescens | Leadplant 



GENERAL BOTANICAL CHARACTERISTICS : 
Leadplant is a native, perennial, rhizomotous shrub 1 to 3 feet (0.3-1
m) tall [16,35,37].  It has erect stems and canescent leaves, topped by
spikelike racemes of purple flowers.  Each raceme contains dozens of
tiny flowers with a single petal wrapped around the stamens and style,
hence its name "Amorpha", a Greek word meaning deformed [38].  The fruit
is a legume with one or two smooth brown seeds (2.2 mm in length) in a
thin, soft, pubescent pod.

The deep, branched, woody root system extends to a depth of 6.5 to 16.5
feet (2.1-5.3 m), with few laterals in the upper 2 to 3 feet (0.6-0.9 m)
of soil [38].  This greatly minimizes competition with grasses for water
and nutrients [38].  The roots of leadplant have nitrogen-fixing nodules
throughout their length [9].


RAUNKIAER LIFE FORM : 
   Chamaephyte
   Geophyte


REGENERATION PROCESSES : 
Leadplant regenerates through both seed and vegetative means [29].
Documentation of leadplant's ability to sprout is scant.  It is
described as "often rhizomatous" [16].  Stems can also regenerate from
the root crown after the top is removed, damaged, or killed [37].
Wright [39] listed leadplant as one of the prominent sprouters in the
central Great Plains, and Weaver [37] stated that stems use the stores
of food in the root crown and very deep taproot while sprouting.

Good seed crops are produced at least every 2 years, with some seeds
produced every year.  One or, rarely, two seeds occur in a thin, soft
pod that does not inhibit germination [8].  In a study on a tallgrass
prairie in Illinois, leadplant seeds were found in the upper 1.2 inches
(2 cm) of soil with 17 percent frequency [20].


SITE CHARACTERISTICS : 
Leadplant occurs in a variety of habitats including dry plains,
hillsides, prairies, open woodlands, shaded ravines, and roadsides.  It
occurs on the mesic portions of mixed-grass prairie in the Northern
Great Plains; on the tallgrass prairie of the central Great Plains,
including the Sandhills in western Nebraska and the Flint Hills of
Kansas; and in the mixed tallgrass-forest of the southern Great Plains
from central Texas and Oklahoma to their eastern edges [40].  It also
occurs on lower slopes and well-drained lowlands dominated by big
bluestem [38].

Leadplant is drought tolerant.  It is common where mean annual
precipitation (MAP) is over 15 inches (380 mm), occurs infrequently on
moisture compensation sites with as little as 12 inches (305 mm) MAP,
but is most productive in areas with 18 to over 20 inches (46-51 mm) MAP
[36].  Leadplant thrives in sandy to silt-textured soils, and is also
tolerant of weakly acid to moderately alkaline and weakly saline soils
[16,30,36].  Regional site information follows.

In the Cross Timbers regions, precipitation varies from 27 to 45 inches
(69-114 cm), and elevation from 500 to 1,000 feet (150-300 m).  Sandy
soils to deep sandy loam and silt loam soils are common [40].

In the central Great Plains tallgrass prairie, elevation varies from
1,000 to 2,000 feet (305-610 m), and annual precipitation averages from
23 inches (580 mm) in eastern Nebraska to 35 inches (890 mm) along the
eastern edge of the prairie; in the Sandhills, precipitation is as low
as 18 inches (460 mm).  Soils are of medium texture except in the
Sandhills of Nebraska and the Flint Hills of Kansas.

The more mesic portions of the northern Great Plains mixed-grass prairie
average 13 to 18 inches (330-460 mm) annual precipitation.  Elevation
ranges from 1,300 to 4,000 feet (400-1,300 m).  Soil textures are
primarily sand, sandy loam, silt loam, silty clay loam, and loam, mostly
developed from glacial till.


SUCCESSIONAL STATUS : 
Obligate Climax Species

Leadplant is a climax species [3] present in several climax grassland
plant communities as well as in ponderosa pine and bur oak habitat types
[19,21].  Weaver and Fitzpatrick [38] called this species the most
conspicuous subdominant of upland tallgrass prairie.  Leadplant is
shade tolerant and grows in partially shaded ravines and open woodlands
[36].  Seedlings are very tolerant of shade but not of competition from
grasses.


SEASONAL DEVELOPMENT : 
Vegetative growth begins in early May when buds open on the woody stems.
Plants begin to flower in late June and in July, and flowers persist for
several weeks.  Seeds mature in August to September and are dispersed in
the fall [8,35,36,38].  In late July and August, especially if water is
lacking, plants may drop their lower leaves, but the remainder of the
leaves stay green until the first frost [38].  The plant usually dies
back almost to the ground nearly every winter [8].

Related categories for Species: Amorpha canescens | Leadplant