Origin and Habitat: It occupies an area of several square kilometres in the province of La Rioja (Northwest Argentina, Southern America)
Altitude: About 500 m above sea level.
Type Locality: General San Martin Department, west of the village of Nueva Esperanza (Las Tres Marias)
Habitat: Gymnocalycium esperanzaeSN|23796]]SN|23796]] grows on low hills with shallow depressions formed by erosion in a dense shrub-land with scattered trees. the substrate is composed by gravel and loamy fine soil. This species grows mostly under the cover of lax shrubs, but also elsewhere, in direct sunlight.

• Gymnocalycium esperanzae Řepka & Kulhánek

Description: Gymnocalycium esperanzaeSN|23796]]SN|23796]] is an attractive species with flattened stems covered with a conspicuous grey bloom.
Roots: Carrot-like unbranched or branched only apically.
Stem: 5-9(-16) cm in diameter and 5-8(-12) cm tall flattened-globose to globose epidermis greenish-brown or greenish-grey with a conspicuous grey bloom.
Ribs; (7-)9-12(-16), straight, shallow and flat in young plants becoming notched in adult specimen..
Areoles: Round to elongate, 7-15(-18) mm apart from each other, slightly sunken, with yellowish, greyish or blackish wool, almost bare with age.
Radial: 3-5(-7) if 3 in number making a T shape, if 5 or 7 in number then the upper pairs the shortest, (8-)12-18(-25) mm long brown, black, bluish-grey, pale purple or horn-coloured.
Central spines: None.
Flower:salver-shaped, (45-)55-60(-70) mm long and 35-40 mm wide; whitish-rose to pale pink, at base often pale purplish or pale rose. Style yellowish-white; stigma pale yellowish, 10-lobed. Stamens-filaments pale greenish, lower part of lower filaments slightly rose, anthers pale yellowish.
Fruit: (20-)22-30(-35) mm long and 15-18 mm wide spindle shape to clavate, greyish-green to bluish-green to pale brownish.
Seeds: Helmet-like, shiny dark maroon to blackish brown, (0,92-)1,0-1,2 mm long and 1,0-1,2(-1,3) mm wide (subgenus Microsemineum).

Notes: Some morphological traits support the hypothesis that Gymnocalycium esperanzaeSN|11483]]SN|23796]] may be a recent hybrid involving Gymnocalycium bodenbenderianumSN|14405]]SN|14405]] and Gymnocalycium castellanosiiSN|23796]]SN|11483]] subsp. armillatum, both of which occur in the surroundings.

Bibliography: Schütziana 2(2011)3 p. 2 ISSN 2191-3099 http://www.schuetziana.org/downloads/Schuetziana_2_2011_3_medium.pdf

Cultivation and Propagation: Easy to grow, these plants offer no cultivation difficulties. Watering Needs: Moderate to copious in summer, keep dry in winter.
Frost Tolerance: Quite frost resistant if kept dry -10° C (Temperature Zone: USDA 8-10 )
Cultural Practices: Feed with a high potassium fertilizer in summer.
Sun Exposure: Full sun to light shade.
Propagation: Seeds (seldom produces offsets)