Opuntia spp. are threatened by an infestation of the cactus moth (Cactoblastis cactorum) that has a distribution encompassing South Carolina southward along the coast to Florida and eastward along the Gulf of Mexico to Louisiana (Sauby et al., 2012: 562). The invasive moth feeds on species of the subfamily Opuntioideae. In Florida, infestation of C. cactorum was more typically on Opuntia stricta and Opuntia humifusa var. ammophila and may be related to their larger sizes and potential to release greater quantities of volatile organic compounds (Sauby et al., 2012: 566).

References

Sauby, K. E., Marsico, T. D., Ervin, G. N. & Brooks, C. P. 2012. The role of host identity in determining the distribution of the invasive moth Cactoblastis cactorum (Lepidoptera: Pyralidae) in Florida. Florida Entomologist 95: 561-568, available at: http://www.bioone.org/doi/full/10.1653/024.095.0304; accessed on: Nov 7, 2012.

Opuntia pusilla, a member of the family Cactaceae, is commonly known as the sandbur or cockspur prickly pear. This species of cactus does not grow to be very tall (<15cm), but instead grows close to the ground and spreads outward to 4.5 m (Loflin & Loflin, 2009: 109; Majure, 2007: 73). Segments, also referred to as cladodes, of the stem are green and usually somewhat flat or cylinder-shaped up to 11 cm in length (Majure, 2007: 75). The segments consist of sharp glochids (small, hair-like barbs that grow in groups) and 1-4 retrorsely barbed spines (up to 6 cm in length) per areole or spine cushopn (Majure, 2007: 37, 76). Opuntia pusilla is identified by having segments that easily break off and get stuck in anything that touches them and this characteristic is a means for dispersal (Loflin & Loflin, 2009: 109, Majure, 2007: 72). In addition, terminal clodes detach on their own and can thus increase the patch diameter (Majure, 2007: 73). Shading can contribute to smaller cladode sizes (Majure, 2007: 74). Opuntia pusilla blooms greenish yellow flowers from April-May and produces red to purple fruits up to 3 cm in length (Loflin & Loflin, 2009: 109).

References

Loflin, B. & Loflin, S. 2009. Texas Cacti. 312 pp. China: Everbest Printing Co.

Majure, L. C. 2007. The ecology and morphological variation of Opuntia (Cactaceae) species in the mid-south, United States. PhD dissertation, Mississippi State University.

Opuntia tracyi Britton:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Opuntia drummondii Graham:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Opuntia pusilla (Haw.) Haw.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Ala., Fla., Ga. , Miss., N.C., S.C., Tex.

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Texas at Rockport and Anahuac; coastal regions from Mississippi to North Carolina, including N. Florida; rare near Ft. Meyers, Florida.

Distribution of Opuntia pusilla is in the coastal parts of southern United States, typically in sand dune systems, pine-scrub forests (Loflin & Loflin, 2009: 109; Majure, 2007: 35). It is most common to coastal dunes in Florida northward to North Carolina and along the Gulf of Mexico to Texas (NatureServe Explorer, 2012).

References

Loflin, B. & Loflin, S. 2009. Texas Cacti. 312 pp. China: Everbest Printing Co.

Majure, L. C. 2007. The ecology and morphological variation of Opuntia (Cactaceae) species in the mid-south, United States. PhD dissertation, Mississippi State University.

NatureServe Explorer. 2012. Available at: http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Opuntia+pusilla; accessed on: Oct 16, 2012.

Shrubs, creeping, often forming mats, trailing, to 0.1 m. Stem segments easily detached, green, purplish red under stress, flattened, elliptic to linear, sometimes subcylindric (to subspheric), 2.5-5(-8) × 1.2-2.5 cm, tuberculate, glabrous; areoles 2-5 per diagonal row across midstem segment, subcircular, 2-3 mm diam.; wool tan to gray. Spines (0-)1-2(-4) per areole, in distal ³/4 of stem segment areoles (to nearly spineless), porrect to spreading, red-brown, aging gray, stout, straight, terete, to 30 mm, strongly barbed. Glochids in crescent at adaxial edge of areole, pale yellow, aging brown, to 3 mm, longest at areole apex. Flowers: inner tepals yellow throughout, 20-30 mm; filaments and anthers yellow; style and stigma lobes white. Fruits green becoming red-purple at late maturity, barrel-shaped, 18-30 × 12-20 mm, fleshy, glabrous, spineless; areoles 8-16. Seeds tan, subcircular, flattened, 4-6 mm diam.; girdle slightly protruding. 2n = 44.

Cactus pusillus Haworth, Misc. Nat., 188. 1803; Opuntia drummondii Graham; O. tracyi Britton

Neotype for Opuntia pusilla (Haw.) Nutt.
Catalog Number: US 3046577
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): J. K. Small
Year Collected: 1916
Locality: Charleston, Folly Island, South Carolina, United States, North America

Dune and pine scrub, primarily coastal, sandy openings, dunes, or rocky outcrops; 0-100m.

Comments: Sand of mostly coastal dunes, beaches, and woods near sea level. Open areas of along edges of deciduous forests.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 80

Comments: Twenty-six EO's (Benson 1982).

Flowering spring (Apr-May).

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Known form the coastal regions from MS to NC, including N. FL, 26 EOs. Rank of S4? from MSHP, TX recommends G4 (4/94).

Opuntia pusilla is rated as critically imperiled in Texas and vulnerable in North Carolina (NatureServe Explorer, 2012).

References

NatureServe Explorer. 2012. Available at: http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Opuntia+pusilla; accessed on: Oct 16, 2012.

Comments: Most cacti subject to horticultural collecting.