Cumulopuntia dimorpha

Structure and variation

Plants form loose branched clusters up to about 30 cm tall and have fibrous roots. Stem segments may be globose, ovoid, oblong or spindle-shaped. Areoles are distributed fairly evenly across their surface, while stronger spines are more often concentrated in the upper part. In the material examined, spines were mostly straight. [Pauca-Tanco and Quipuscoa 2020]

Two growth forms were associated with site elevation. At lower sites, about 1900–3300 m, loose dwarf shrubs with elongated stem segments were more frequent. Higher up, smaller, loosely cushion-forming plants with shorter segments also grew, sheltered by rocks or other plants. Field observations confirm that a spindle-shaped segment falls within the natural variation of the taxon described. [Pauca-Tanco and Quipuscoa 2020]

Siedlisko

In Arequipa, the species was recorded from 1900 to 3660 m in numerous valleys and on slopes, including within the Batolito de la Caldera. It occupies sandy and stony substrates on gentle or moderate slopes, often near drought-adapted shrubs and other cacti. The revision indicates occurrence in Peru and Chile. [Pauca-Tanco and Quipuscoa 2020]

Flowers, fruits and phenology

Flowers open during the day, are yellow and may turn orange as they wilt. The fruit has a dry seed chamber. In the populations studied, flowering occurred in July–October and fruiting in November–January. Visits by hymenopterans, beetles, butterflies and occasionally hummingbirds were recorded. [Pauca-Tanco and Quipuscoa 2020]

Historia nazwy

The authors of the 2020 revision published the combination Cumulopuntia dimorpha and designated a neotype for the original name Opuntia dimorpha. In older accounts, the plant also appears as Tephrocactus dimorphus. Characters of stem segments, fruits and seed coverings matter in comparison with broadly treated C. sphaerica. [Pauca-Tanco and Quipuscoa 2020] [2-WWW]