Scientific name: Mammillaria pseudoalamensis Backeb
Britton & Rose, published in: The Cact. 4: 156 1923
Origin: Sonora and Chihuahua.
Conservation status: Listed in
CITES appendix 2.
Description: Mammillaria sheldonii is
undoubtedly a variable species, which has given rise to several names now
ascribed to synonymy.
The M. pseudoalamensis (= M. alamensis) is nothing else
than a variant recognisable for the absence of central spines,
flowers with a characteristic distinctive orange pistil. Habit:
It makes a
cluster of basal stems.
Stem: spherical to slender-cylindrical, dull green, often becoming
reddish, 3-6 cm wide, 8-15 cm tall (or more in cultivation)
Tubercles: Cylindrical four-sided basally, carinate, without
latex, axils without wool but with an occasional few bristles.
arrangement: 8 - 13
Radial spines: The number of radial spines varies from as low as
9 (M. alamensis) to as many as 24, white, tipped brown, needle-like,
about 6 to 8 mm long.
Central spines: 1 to 4 ( 0 in M. alamensis), the lower
elongated and either straight or hooked, 1 to 15.cm long, brownish, the
upper part dark blackish brown.
Flowers: Large, wide funnel-form, diurnal,
inodorous, light purplish-pink with a pinkish brown midstripe and
paler margins, about 20 cm in diameter (up to 3,5 in M. alamensis).
Stigmas are green (Orange in M. pseudoalamensis)
Blooming season: Spring, and flowers remain open for about three or four
Fruits: Club shaped, pale scarlet 25-30 mm long.
Photo of conspecific
taxa, varieties, forms and cultivars of plants
belonging to the Mammillaria
Taxon has lots of synonyms ( like many other cacti),
with several controversial varieties and
subspecies, and comprises a multitude of
different forms, but where each form is linked to others by populations
of plants with intermediate characteristics):