BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Mahonia trifoliolata | Agarito 



GENERAL BOTANICAL CHARACTERISTICS : 
Agarito is a dense, thicket-forming evergreen shrub which grows 3 to 10
feet (1-3 m) in height [1,46,51,52].  Twigs are smooth and reddish-green
when young but turn gray to reddish-brown with age [52].  Bark is gray
to reddish-brown and often exfoliating [28,52].

The alternate, trifoliolate leaves are stiff, spiny, and hollylike
[1,35,52].  Leaflets are thick and coriaceous, lanceolate-oblong to
elliptic, and have coarsely serrate or spinose margins [1,28,52].
Leaflets are pale green to glaucous [28].  

Yellowish, perfect flowers are borne in few-flowered racemes at the
upper axils or terminally on short shoots [28,52].  Fruit is a
subglobose to globose berry, 0.3 to 0.5 inch (8-12 mm) in diameter
[1,28].  Berries are lustrous, and red or black to pruinose blue
[1,28,35].  The pulpy fruit is acidic and aromatic [52].  Fruit is borne
on short pedicels which are tightly appressed to the stem axis [24].
Each fruit contains one to several seeds [52].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Agarito reproduces through seed and sprouts vigorously following most
types of disturbance.

Seed:  Agarito produces an abundance of seed nearly every year [43].  In
related species of mahonia, annual fruit production is sometimes reduced
by poor pollination and adverse weather conditions.  The specific
genetic composition of individual plants can also influence fruit
production [24].  Seed of agarito is dispersed during the summer by a
variety of birds and mammals.  Under natural conditions, seed germinates
the following spring [43].

Vegetative regeneration:  Agarito typically sprouts vigorously from the
roots or root crown after aboveground vegetation is removed or damaged
[11,19].  Box and others [11] reported that agarito sprouts from or near
ground level after fire.  After mechanical removal, Cross and Wiedemann
[19] observed sprouting from lateral roots and from crown tissue
attached to the taproot.  The majority of regrowth (56 percent) was
attributed to lateral root sprouting, whereas 13 percent was derived
from crown tissue.  No sprouts were observed on the taproot itself.


SITE CHARACTERISTICS : 
Agarito grows in a variety of habitats including flat pastureland, lower
alluvial flats, in ephemeral drainage channels, on mesa sides, and on
dry, stony hills [3,18,35,40,52].  Agarito grows well on sunny sites
[51].  It is often well represented in riparian areas and in bottomland
communities of the rolling Texas plains [18,20].

Soils:  Agarito grows on a variety of soil textures including loam,
clay, shallow clay-loam, and gravelly soil [19,22,39,51].  Soils are
commonly dry and well drained [51].  Agarito often occurs on soils
derived from limestone parent material [15,50].

Climate:  Agarito grows in semiarid climates with average annual
precipitation estimated at 22 to 30 inches (55-76 cm) [19,22].  Winters
are typically short and mild, with as many as 283 frost-free days per
year [9].

Elevation:  Agarito grows at approximately 3,000 feet (914 m) in Arizona
[32].


SUCCESSIONAL STATUS : 
Grasslands:  Agarito is a common woody invader in semiarid grasslands of
Texas [19,22].  On the Edwards Plateau, mixed prairie has given rise to
a scrub oak-juniper disclimax in which agarito occurs as a prominent
woody species [42].  In many semiarid grasslands of Texas, redberry
juniper is a common invader on overgrazed sites.  The presence of large
junipers consequently facilitates the establishment and spread of
agarito [39].

Texas savannas:  In south Texas savannas which have been gradually
invaded by honey mesquite, species such as Texas pricklypear (Opuntia
lindheimeri) and prickly ash (Zanthoxylum fagara) assume dominance
during years 12 to 26.  Sugarberry, Texas persimmon, and lotebush
condalia commonly dominate 29- to 39-year-old stands, while agarito,
desert yaupon (Schaefferia cuneifolia), and lotebush dominate 36- to
45-year-old stands [2].  Agarito may eventually be lost from climax
stands [3].

Desert shrub communities:  Agarito invades disturbed desert shrub
communities including those in the Guadalupe Mountains of New Mexico.
It commonly appears in the "last stages of community degradation" [54].
Once vegetation has reached this level of degradation, recovery may be
unlikely.


SEASONAL DEVELOPMENT : 
Fruit ripens from April through July [51,52], but reportedly reaches
peak ripeness on approximately May 1 [24].  Generalized flowering and
fruiting dates by geographic location are as follows:

  Location        Flowering      Fruiting    Authority

  Southwest       ----           July        Vines 1960        
            
  Great Plains    March-April    June        Great Plains Flora
                                             Association 1986

Related categories for Species: Mahonia trifoliolata | Agarito