BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Opuntia humifusa | Eastern Prickly-Pear 



GENERAL BOTANICAL CHARACTERISTICS : 
Eastern prickly-pear is a native, low clump- or mat-forming cactus, usually 3 to
4 inches (7.5-10 cm) in height.  It occasionally grows to 12 inches (30
cm) in height in Florida.  The succulent stems or pads are from 1.5 to
4 inches (3.8-10 cm) long and from 1.6 to 2.4 inches (4-6 cm) wide.
Zero to two spines are found on the upper areoles of stems.  Fruits are
fleshy and persist until spring.  The fiberous roots lack prominent
tubercules [2,10].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte
   Stem succulent


REGENERATION PROCESSES : 
Sexual:  Eastern prickly-pear cactus reproduces by seed.  Seed is disseminated
when seed-bearing fruits drop from mature stems in spring [2], or by
frugiverous birds and mammals.  Clustered populations of eastern prickly-pear are
sometimes established when ground squirrels gather seed from animal
droppings and store them in caches [28].  Germination is slow in this
genus [29].  Flowers are produced at 2 years of age [8], and are
pollinated by insects [19].

Vegetative:  Eastern prickly-pear cactus reproduces asexually from semiprostrate
stems, which root in soil [29].  The genus can sprout from the caudex
when the aboveground portion of the plant is destroyed [5].


SITE CHARACTERISTICS : 
Eastern prickly-pear cactus grows on open, sunny, dry flats or south-facing
exposures with up to a 50 degree slope.  Soils vary from organic
detritus to shale-loam, sandy loam, coastal beachland and Lakewood sand.
The species tolerates low-nutrient, acid, and alkaline soils [2].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Eastern prickly-pear cactus colonizes disturbed sites and may persist through
late seral stages of plant succession.  It colonizes bare coastal dunes
in some areas of the Northeast [27].  On the dunes of southern Lake
Michigan, it appears in early seral stages, where it invades the
beachgrass (Ammophilia breviligulata)-prairie sandreed (Calamovilfa
longifolia) communities of young dunes.  It is found in late seral,
shrub-populated dunes on the shores of western Lake Michigan [22], and
in climax sand sage (Artemisia filifolia) communities in northeastern
Colorado [24].  It is probably a relict in climax communities, however.
Eastern prickly-pear is shade-intolerant [17] and is generally replaced by other
species in advanced stages of succession [2].


SEASONAL DEVELOPMENT : 
Eastern prickly-pear cactus produces flowers and fruits year-round in semiarid
regions of the Southwest [19].  In southwestern Wisconsin, flowers
appear in June, fruits ripen in late summer and fall, and drop in early
spring [7].

Related categories for Species: Opuntia humifusa | Eastern Prickly-Pear