Gymnocalycium Pfeiffer ex Mittler (1844:124)

Oliveira, Anabela Silveira De, Pontes, Rodrigo Corrêa, Robaina, Luis Eduardo De Souza & Trentin, Romário, 2022, The Cactaceae family in the Santa Maria river basin (Rio Grande do Sul, Brazil), Phytotaxa 542 (2), pp. 153-166 : 161

4. Gymnocalycium Pfeiffer ex Mittler (1844:124)

Type (designated by Haworth 1816: 137):— Gymnocalycium gibbosum (Haworth 1816: 137) Pfeiffer ex Mittler.

Species richness:— Gathers approximately 50 species, four species occur in Rio Grande do Sul ( Kiesling 2005).

General distribution:— Gymnocalycium is distributed in southern Brazil, Uruguay, Argentina, Paraguay, and Bolivia.

Distribution in Santa Maria river basin:— Two species were found, Gymnocalycium denudatum (Link & Otto 1828: 9) Pfeiffer ex Mittler (1844: 124) ( Fig. 2K ), and G. uruguayense (Arechavaletae 1905: 218) Britton & Rose (1922: 172) ( Fig. 2L ), they are widespread in the study area and grow on rocky outcrops and the Saxon vegetation, tolerate low light.

Morphologic notes:— These are usually solitary or clustered plants, globose of more than 4 cm in diameter, 4–15 sides, bell-shaped, white calyx, pink or yellowish-white flowers. Dried or fleshy fruits up to 3 cm in length. They usually bloom from October to December, bearing fruit soon after.

Figures

FIGURE 2. A) Cereus hildmaninanus (whitish-pink flowers). B) Echinopsis oxygona (pink flowers). C) Frailea albifusca. D) Frailea castanea. E) Frailea albifusca.F) Frailea lepida.G) Frailea mammifera. H) Frailea pumila. I) Frailea pygmaea.J) Frailea erythracantha K) Gymnocalycium denudatum (white flowers). L) Gymnocalycium uruguayense (yellow flowers). Pictures by A. S. Oliveira.