Opuntia austrina Small. Southern Prickly Pear, Florida Prickly-pear. Phen: Late Mar-May; Jul-Nov. Hab: Florida scrub, longleaf pine sandhills, and transitional areas between Florida scrub, longleaf pine sandhills and pine flatwoods, dunes, shell middens, in deep, sandy soils. Dist: Apparently endemic to FL occurring throughout most of the state but most common in the peninsula and mostly absent from the Panhandle.

ID notes: Opuntia austrina is an erect shrub or treelet, and often semaphore-like with a primary central trunk and most of the branches towards the top of the plant, but growth form is highly variable in this species and some plants are "shrubbier" with lower branches than others; tuberous roots often present, as compared to O. mesacantha, which is a low, spreading species that has fibrous roots. Some plants of O. austrina can reach heights of up to 2 m.

Origin/Endemic status: Endemic

Taxonomy Comments: Opuntia austrina has frequently been confused with O. stricta var. stricta (e.g., see Y) due to its large size and the often straight, rounded (in cross-section) spines, which are similar to those of O. stricta var. stricta. Also, both species occur sympatrically along parts of the Atlantic Coast. This species has been heavily impacted in parts of its distribution by the cactus moth, Cactoblastis cactorum Berg. A diploid species (2n=22). See Majure et al. (2017) for extensive discussion about variation in the species that has led to the extensive synonymy.

Synonymy ⓘ: = S13, Majure et al (2017); = Opuntia compressa (Salisb.) J.F.Macbr. var. austrina (Small) L.D.Benson; > Opuntia ammophila – K3, K4, S, Britton & Rose (1937), Ward (2009e); > Opuntia atrocapensis Small – S; > Opuntia austrina Small – K3, K4, S, Britton & Rose (1937), Ward (2009e); > Opuntia compressa (Salisb.) J.F.Macbr. var. ammophila (Small) L.D.Benson; > Opuntia cumulicola Small – S; < Opuntia humifusa (Raf.) Raf. – WH3; > Opuntia humifusa (Raf.) Raf. var. ammophila (Small) L.D.Benson – FNA4, K1, Benson (1982), Doyle (1990); > Opuntia humifusa (Raf.) Raf. var. austrina (Small) Dress – K1, Benson (1982), Doyle (1990); >< Opuntia humifusa (Raf.) Raf. var. humifusa – FNA4; > Opuntia nitens Small – S; > Opuntia pisciformis Small – S, Britton & Rose (1937); > Opuntia polycarpa Small – S; > Opuntia turgida Small – S, Britton & Rose (1937)

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Heliophily ⓘ: 9