Sphaeropuntia Guggi

Walter, Helmut E. & Guerrero, Pablo C., 2022, Towards a unified taxonomic catalogue for the Chilean cacti: assembling molecular systematics and classical taxonomy, Phytotaxa 550 (2), pp. 79-98 : 87

Sphaeropuntia Guggi :

— Nyffeler & Eggli (2010) remarked that the exclusively West-Andean species Cumulopuntia sphaerica (C.F.Först.) F. Anderson “is unambiguously shown as a separate lineage”, as it appears in a trichotomy with Austrocylindropuntia Backeb. and Cumulopuntia F. Ritter ( Wallace & Dickie, 2002) . Also, in Griffith and Porter (2009) the two accessions of C. sphaerica were not placed within the C. boliviana clade, but in a strongly supported trichotomy with Austrocylindropuntia . Finally, Ritz et al. (2012) showed that the well-supported C. sphaerica clade is sister to the C. boliviana clade.

The morphology of Sphaeropuntia support above mentioned findings. In fact this genus differs from Cumulopuntia in many character states: shrubs low, 10–15 cm high, forming loose groups <50 cm diameter (20–50 cm high, forming compact mounds 0.5–2.0 m diameter); stem segments easily despatching (not so), spherical to short ovoid (long conical to nearly cylindric), epidermis with white wax (not so), not or only slightly tuberculate (strongly tuberculate); areoles evenly dispersed all over the segment (only upper third, crowding near apex), large, 5–10 mm (small, ≤ 5mm), prominent (not so), closely set (more apart); spines 3–5 cm (3–15 cm), present on all areoles (only superior ones spiniferous); floral areoles dispersed all over pericarpel and hypantium (only rim of hypanthium); pericarpel short and broader than long (isodiametric or long); fruits globose to obconical, often broader than high (cylindric), 2.0–2.5(–3.5) cm, areoles large, spiny all over (small, spines only at rim); flank of seeds not ridged (ridges present; see also Stuppy 2002). Moreover, both occur in different habitats: Sphaeropuntia is distributed between the latitudes of 33° S and 18°S and from sea-level to the Pre-Cordillera (100–3700 m), while members of the genus Cumulopuntia are mainly distributed in the Altiplano regions (3700–4300 m). According to these findings we accept Sphaeropuntia Gucchi.