(Rancho Labuerra, Baja
is an unusual plant in collections that require acid organic soil.
Scientific name: Mammillaria
phitauiana (E.M.Baxter) Werdermann in Backeberg.
description by Baxter, Journ. Cact. Succ. Soc. 2:471 (1931)
[Also: Neue Kakt. 96, 1931]
Found by Baxter at east of Todos Santos, Sierra de la Laguna, in the
southern tip of the state of Baja California , Mexico.
It grows in open plains and low hills under the protection of small
scrubs, brushwood and trees on granitic rocks. The soil is acidic and
rich in humus, since the organic rest, the shade and the humidity of the
coast, favor this condition. Altitude to 450 m.
Conservation status: Listed in
CITES appendix 2.
Mammillaria verhaertiana Boedeker = status doubtful.
In: Monatschrift fur kakteenkunde 22: 152 - 153,
phitauiana is a small cactus solitary at first, later forming clusters
from basal branches.
Short-cylindric to culumnar, pale-green 25-30 cm high and 4-5 cm
in diameter. Without latex.
Tubercles: Quadrangular sub-conical, 7 mm long and 6 mm in
diameter, keeled. Axil with some short white wool and silky bristles.
Radial spine: 18 - 24 (usually 20), yellowish white,
bristle-like, radiating, 4 - 12 mm long, lower one the longest.
Central spine: 4(-6) , straight or with one of them hooked, white
with brownish tips, to 12 mm long.
Flower: White, yellowish white or cream with pale pink to brown
small midstripes, 20-25 mm long and 15-18 mm in diameter. Often failing
to open completely.
Fruit: Club-shaped, red, 15 - 30 mm long, 6 - 10 mm in diameter.
Seed: Black, 0,8 - 0,9 mm long and 0,6 mm wide
Blooming season (Europe): From May- June.
Cultivation: It is a slow
growing species. Water occasionally in winter so the roots do not
dry out completely, and water regularly in summer.
Some growers suggest
to use exclusively rain water. But be careful, as it will rot easily if
the substrate is wet and cold. It tends to lose its roots in winter.
The root system of this plant is comparatively small, and it is best to
grow it in a shallow with good drainage pot using a very porous and slightly acidic compost, with
plenty of extra grit. Give an occasional tonic of sequestrated iron. Feed with a high potassium
fertilizer in summer.
Usually it is recommended to
overwinter this plant in a bright and warm greenhouse with at least
8-10° C , but it proved to be quite
(if kept dry it is hardy as low as -5° C)
Strong light (but not direct sun) is required for flowering.
Some plants will offset readily, and clumps can be
produced in a very few years.
Propagation: Direct sow after