Coriphantha poselgeriana is a heavily spined, imposing species,
and reminds one of an Echinocactus. The nomenclature of this variable
taxon is quite confusing.
Stem: Globular to short cylindrical, solitary or slowly clumping,
reaching up to 30 cm in height and 18 cm in width. Dull bluish green,
apex rounded and woolly.
Roots: Thin taproot.
Tubercles: Up to 2(-3) cm long and 5 cm wide, convex, conical, 4-6
edged with a deep wooly groove, near the areole, rounded near the end.
Parastichy number 8-13. With yellow-orange glands over the whole length.
Axil woolly with glands.
Areoles: About 7 mm wide, round with short wool.
Radial spines: 5 to 12, with 7-8 of them radiating sideways and
downwards, straight or recurved, strong, subulate, the 3-4 lower ones
are somewhat fattened, up to 30-40 mm long.
Whitish, later reddish
darker tip and ultimately greysh.
Central spines: 1, straight, porrect, with light tip.
Similar in shape and colour to lower radials.
Flowers: 6-7 cm, varying from whitish-rose with a pink centre,
to carmine red, and in San Luis Potosí even yellow-flowering forms
Fruits: Green, juicy, with persisting flower remnants. 25-50mm
long, 7-18 in diameter.
Seeds: Reniform 2-2,5 mm long, 1,5 mm wide.
clinal species have two forms, often referred
to as distinct varieties or
subspecies. The forms
from North of the Sierra de Paila are more strongly
spined (var. valida) than the ones to the
South, which have
more radials (var. saltillensis). But the transition is
continuous, and separation of a subspecies is questionable.
Cultivation: This plant grows in the same habitat as
Echinocactus horizonthalonius, with which it has some
cultivation problems in common: slow-growing, seldom reaching the same
size as in nature, sensitive against over-watering.
needs good drainage. Keep drier in winter. Full sun to partial shade.
Full sun to
partial shade. I
nectar (if not completely removed by ants) can cause the formation
which leads to ugly black-colouring of the
epidermis. To prevent this, spray the plant with water to remove the
nectar. And provide very good