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
Description: Small barrel cactus, usually solitary but
Stem: Depressed globose to shortly cylindrical,
up to 30 cm in
diameter, 25 cm tall, occasionally much taller;
Ribs: 12-20 narrow,
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.).
Scientific name: Ferocactus alamosanus
(Britton et Rose) Britton et Rose 1922
Known only from a restricted area in the mountains at
East of Alamos, Sonora, Mexico. Said to be heading for endangered
Conservation status: Listed in
CITES appendix 2.
- Echinocactus alamosanus Britton
et Rose 1913
- Ferocactus alamosanus var. platygonus
- Ferocactus alamosanus ssp. reppenhagenii
(G. Unger) N.P. Taylor
Pubblished in: Cactaceae Consensus Initiatives 6: 15, 1998
- Ferocactus reppenhagenii G.
Pubblished in: Kakt. And. Sukk., 25 (3): 50., 1974
- Ferocactus alamosanusvarp. reppenhagenii
- Ferocactus pottsii var. alamosanus.
- Parrycactus alamosanus ssp. reppenhagenii,
Taxon belong to a group of six closely
allied species. The group is: F.
F. glaucescens, & F. echidne)
F. alamosanus which flowers early in spring.
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.
Exposure: Outside they need a bright exposure,
full sun or half shade in summer if the location is exceedingly hot or
bright, inside needs bright light, and some direct sun.
It can tolerate moderate shade, and a plant that has been growing in
shade should be slowly hardened off before placing it in full sun as the
plant will be severely scorched if moved too suddenly from shade into
Frost Tolerance: Light frost protection required for
safe cultivation, but can tolerate sporadic light frost. This
plants need a period of cool rest in winter to produce flowers
Diseases and pests:
Watch for infestations of
mealybug, scale insects and spider mite.
Plant in good conditions will
start to bloom when reach the diameter of only 15-18 cm.
Seeds are the only way of
Fruit must be significantly
overripe before harvesting seed; clean and dry seeds
conspecific taxa, varieties, forms and cultivars of plants belonging to
the Ferocactus pottsii
Taxon has lots of synonyms ( like
many other cacti) whit controversial varieties and subspecies: