Family: Cactaceae(Cactus Family)
Scientific name: Ferocactus glaucescens (DC.) Britton & Rose forma nuda (inermis)
Origin: Garden origin (Nursery produced cultivar)
Conservation status: Listed in CITES appendix 2.
Common Name: Blue Barrel Cactus
Ferocactus glaucescens var. nuda
This distinctive variety has recently been introduced and is a real prize as it has few or no spines.
Spineless with woolly top. This cultivar varies from pure nude specimens to plants with one or few spine per areoles (Partially Nudum), but usually the spines are present only in young plant and completely disappear in mature individuals.
Description: Solitary or basally suckering, barrel cactus. Multiple heads are produced as the plant ages and can form a very large mound.
Stems: Glaucous grey, up to 55 cm in height, 50 cm in diameter. Globular depressed at the apex, it becomes shortly columnar as it ages.
Ribs: 11 to 15
Spines: Absent or very few (1 to 3 not distinguishable from radials to centrals) irregularly scattered on the areoles of young individuals.
Flowers: Lemon yellow, funnel-shaped, 3-4 cm in diameter. The tepals are oblong, lanceolate, silky, shining; the margins are finely fringed. Stamen, style and stigma are yellow. Stigma lobes: 12-15.
Blooming season: Late spring and summer. The flowers last a very long time. The plants start flowering when about 13cm in diameter.
Fruit: White, 2 cm long with the remnants of the flowers attached.
Cultivation: Plants are slow-growing to start, but they are easy to grow and require little care once they have reached a nice flowering size. F. glaucescens is suited for any rich, well drained soil in full sun throughout the year. Pot culture: it grows best in a fairly roomy, well-drained container filled with a porous cactus soil mixture that doesn't contain too much humus. To insure robust plants, water and fertilize during the aestival growth cycle; this plant need plenty of water (indicatively, about once a week). But it's necessary to avoid wetting the bodies of these plants while they are in sunlight. A wet cactus in the sun light can cause sun burning, which can lead to scars or even fungal infections and death. In winter keep it completely dry at 10°C. This usually aids in maintaining a healthier plant, but can tolerate sporadic light frost.
Reproduction: Cuttings (if available) made from pieces of the stem of any size can be detached and laid aside for a few days to allow a protective "skin" to form over the cut. They can then be planted in pots. Place them in a spot where they'll receive sun, and do not water until the soil becomes fairly dry. After a while the soil can be moistened regularly but never kept constantly saturated.