BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Mimosa biuncifera | Catclaw Mimosa 



GENERAL BOTANICAL CHARACTERISTICS : 
Catclaw mimosa is a relatively short, straggling, thicket-forming,
deciduous shrub.  It is usually not more than 3 feet (0.9 m) tall but
occasionally grows up to about 8 feet (2.4 m) [6,24].  The pubescent,
slender, straight to zig-zagging stems are armed with solitary or
paired, stout, recurved spines [39].  The bipinnately compound leaves
contain 3 to 9 pair of pinnae with 8 to 14 pairs of obtuse, linear to
oblong, 0.04 to 0.17 inch (1.0-4.2 mm) long leaflets [39].  Numerous
pale to whitish flowers occur in globose heads.  The fruit is a curved
or straight legume, 0.75 to 1.5 inch (1.9-3.8 cm) long, 0.13 to 0.17
inch (3.2-4.2 mm) wide, and is constricted between the seeds.


RAUNKIAER LIFE FORM : 
   Phanerophtye


REGENERATION PROCESSES : 
Catclaw mimosa produces abundant seed.  Seeds are encased within small,
narrow pods that split open after ripening [34].  Primary dispersal
agents have not been identified, but seed is probably dispersed by
animals that eat the pods or seeds.  Catclaw mimosa seeds exhibit high
germination rates and germinate over a wide range of temperatures [22].
On the High Plains of west Texas, redberry juniper (Juniperus
pinchottii) acts as a nurse plant for catclaw mimosa.  The closed canopy
and heavy mulch layer associated with redberry juniper apparently
provides a favorable microenvironment for catclaw mimosa seedling
establishment [28].

Catclaw mimosa sprouts from the root crown following damage to the
aboveground portion of the plant, such as by fire or herbicides [19[.


SITE CHARACTERISTICS : 
Catclaw mimosa occurs on gravelly flats, mesas, and rocky slopes in
desert grass, desert shrub, interior chaparral, pinyon-juniper, open
oak, and pine-oak communities [6,12,24,29,40].  

Soils:  In western Texas, catclaw mimosa often occupies soils derived
from limestone or igneous rock [34].  

Elevation:  Elevational ranges are presented below [4,24,34]:

from 2,000 to 5,000 feet (610-1,524 m) in w TX
     3,000 to 6,000 feet (914-1,829 m) in AZ
     4,300 to 5,600 feet (1,311-1,707 m) in the Rincon Mtns, se AZ 


SUCCESSIONAL STATUS : 
Catclaw mimosa is a common component of interior chaparral, a vegetation
type considered to be a true climatic climax susceptible to large-scale
burning [6].  This plant's sprouting ability allows it to become a part
of the immediate postfire community.  Individual plants may live to be
very old, although the aboveground portion may date back only to the
last fire [33].

Catclaw mimosa is considered an invader of desert and semiarid
grasslands [20,34].  Fire suppression and livestock grazing are thought
to be responsible for the spread of shrubs into what is considered to
have been relatively shrub-free grasslands of the Southwest [41].
Although catclaw mimosa is fire tolerant and a high percentage of plants
survive fire, a combination of frequent fires, droughts, competition,
and browsing by rodents and lagomorphs may have suppressed plants in
presettlement times [41].  Cattle reportedly "devour the pods" [10].
This undoubtedly has aided the spread of catclaw mimosa into grasslands
because seeds are probably scarified as they pass through the digestive
tract and are then deposited in nutrient-rich dung, which aids
germination.


SEASONAL DEVELOPMENT : 
The time of flowering for two Southwestern states is presented below:

    State          Time of Flowering        Authority

     AZ               May - August            [24]
     TX            April - September          [34]

Related categories for Species: Mimosa biuncifera | Catclaw Mimosa