Scientific Name
Gymnocalycium denudatum (Link & Otto) Pfeiff. ex Mittler
Common Names
Spider Cactus
Synonyms
Echinocactus denudatus
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Trichocereeae
Genus: Gymnocalycium
Description
Gymnocalycium denudatum is a small, usually unbranched cactus with a spherical, glossy dark green stem with rounded ribs and spines flattened against the body in shape of little white or pale rose spiders. The stem grows up to 4 inches (10 cm) tall and up to 6 inches (15 cm) in diameter. Flowers are creamy-white, up to 3 inches (7.5 cm) in diameter, and appear in spring and summer.
Photo via gymnocalycium.wordpress.com
Hardiness
USDA hardiness zones 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).
How to Grow and Care
Some Gymnocalyciums are shade-seeking in the wild, among shrubs or grasses, while others grow completely exposed. Therefore, some will need a light shading from the sun in the hottest months, but to overdo, this will result in the loss of flowers.
The potting medium's balance should be sufficient to allow good drainage so that the plants do not sit in soggy soil for more than a day or two after watering.
Watering in the summer months, while the plants are growing well, can be frequent (weekly for small plants in small pots), but always allowing the compost nearly to dry out before rewatering. Watering in the winter months at all is unwise and certainly not necessary. The difficult times are spring and autumn.
Those species which produce offsets can be readily propagated by cuttings. Gymnocalycium seed germinates well when fresh and will keep for a few years if stored in cold conditions. See more at How to Grow and Care for Gymnocalycium.
Origin
Native to Brazil (the Rio Grande do Sul), Uruguay (Melo), and probably Paraguay.
Links
- Back to genus Gymnocalycium
- Succulentopedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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