Xerophyte

Central Spines

None.

Seeds

Black, spherical, 1.1 mm long and 0.95 mm in diameter.

Description

This is a small solitary or clustered species, that grows almost buried in the soil, it has a characteristic feathered appearance.

Roots

Large taproot up to 10 cm long.

Note

It is probably only a neotonic (juvenile form which remains so) form of Mammillaria lasiacanthaSN|1835]]SN|9075]] rather than a good species, or a subspecies or simply an aberrant form of one of the Mammillaria lasiancantha group species.. The two plants looks different, but clearly related.

Tubercles

Conical, somewhat soft, dark green to brownish green, 3 - 4 mm long, 2 - 3 mm in diameter. The axil is naked

Flowers

Funnelform, 13 - 15 mm long and wide, whitish to cream- colored with green flush. Inner petals with pink midveins on the sepals. Stigmas are yellow. The placement of the flowers is very different from typical lasiacanthae species, in which the bud emerges from axils very close to the apex, of the plant. Mammillaria roemeri presents its flowers from older areoles, mid way down the body of the plant, in the fashion of Mammillaria crucigeraSN|9075]]SN|1835]] or huitzlipochtlii, although it must be emphasised there is no suggestion of kinship between it and these.

Blooming Season

In habitat it flowers between November and January, but in cultivation (Europe) its bloom appear in April.

Stem

Without latex, flattened, globose, sunken apically, solitary or clumping, 10 - 20 mm high and to 35 mm in diameter.

Radial Spines

25 - 32, radiating, straight or curved, feathery , glassy white, 1.5 - 2.3 mm long, soft.

Fruits

Green, 3 - 4 mm long and 3 mm wide.