1.
Acanthocereus tetragonus
(Linnaeus) Hummelinck, Succulenta (Netherlands). 20: 165. 1938.
Barbed-wire cactus, triangle cactus, chaco
Cactus tetragonus
Linnaeus, Sp. Pl. 1: 466. 1753
; Acanthocereus floridanus
Small ex Britton & Rose;
A. pentagonus
(Linnaeus) Britton & Rose;
Cereus pentagonus
(Linnaeus) Haworth;
C. tetragonus
(Linnaeus) Miller
Shrubs,
clambering or arching-reclining, branched near base, sometimes with well-developed trunks.
Stems
dark green, growing to 200 cm per season; ribs from base to rib crest 3-5 cm, less than 1 cm thick.
Spines
abruptly thickened at base, extremely variable.
Flowers
14-20 cm; flower tube 8-15 cm, ± tuberculate, areoles few, usually 1 spine per areole; outer tepals narrowly lanceolate to linear, 3.5-4 cm, apex acuminate; inner tepals broadly linear, 3.5-4.5 cm, apex acuminate; ovary with small scales and usually 3-5 diverging spines per areole.
Fruits
bright red, ovoid to oblong, 30-80(-100) mm, slightly tuberculate, shiny, edible, sweet.
2
n
= 22 [as
A. pentagonus
(Linnaeus) Britton & Rose].
Flowering mid summer-fall. Sandy soils of dense thickets, hammocks, bottomlands of coastal areas; 0-10 m; Fla., Tex.; Mexico; West Indies; Central America; n South America; introduced Pacific Islands (Hawaii).
The Florida populations have been called
Acanthocereus floridanus
but now appear to be the northernmost variants of the highly variable species
A. tetragonus
, which occurs throughout the Caribbean region (D. R. Hunt 1991).
The common name "triangle cactus" refers to the mature stems in cross section; the epithet "
tetragonus
" alludes to the juvenile stems, which often have four angles.
