Sometimes referred to as F. pottsii var. alamosanus, this rare and distinctive barrel cactus has relatively delicate spines for a Ferocactus, and is very hard to find a good size plant like this in cultivation.
Scientific name: Ferocactus alamosanus (Britton et Rose) Britton et Rose 1922
Origin: Known only from a restricted area in the mountains at East of Alamos, Sonora, Mexico. Said to be heading for endangered species list.
| Description: Small barrel cactus, usually solitary but sometimes clumping.
Stem: Depressed globose to shortly cylindrical, up to 30 cm in diameter, 25 cm tall, occasionally much taller;
Ribs: 12-20 narrow, acute ribs.
Spines: Needle-like. Densely intermeshed with a reddish tinge in the new growth
Central spine: 1, sometimes flattened, up to 6 cm long;
Radial spines: 8, straw-coloured, 3 to 4 cm long .
Flowers: Wide open greenish yellow, up to 4.5 cm long, 3.5 cm in diameter. The petals are spatulate and broad.
Fruit: Dull brown-red fruits splitting open when ripe.
Taxonomy note: The differences with Ferocactus pottsii are in reality very small, the ribs in F. alamosanus are more numerous and the central ribs is more long, The subspecies 'alamosanus' has usually about 20 acute ribs, heavy spination, and only grows to 25 cm high. The subspecies 'reppenhagenii' has 12-18 rounder ribs and connecting areoles and will grow up to about 70-100 cm.).
Cultivation: They are summer-growing and pretty easy plants thought slow to start. They are suited for any rich, well drained soil such us clay, pumice, lava grit, and only a little peat or leaf-mould. If potted, repot them preferably in the spring, if their roots become cramped. Generally, they should be repotted every other year in order to provide fresh soil. However, this doesn't necessarily mean they'll need larger containers. Fill about a quarter of the pot with broken crocks, gravel, etc. to promote good drainage. After repotting, do not water for a week or more. Water regularly during the aestival growth cycle (this plant need plenty of water, but do not overwater and let their soil dry out between waterings), and also needs to be avoided wetting the body of this plant while it is in sunlight. A wet cactus in the sun light can cause sun burning which can lead to scares or even fungal infections and death, keep rather dry in winter. No water should ever be allowed to stand around the roots. Feed with a high potassium fertilizer in summer.
Propagation: Seeds are the only way of reproducing.Seed Collecting: Permit fruit to ripen. Fruit must be significantly overripe before harvesting seed; clean and dry seeds