Xerophyte

Description

The peculiarity of the ''sanluisensis'' variety is the presence of spines in the areoles, this characteristic is sometime found also in the plant from Tula (even if very rare), while most of the plant from San Luis Potosi are spiny. The plants from the different known populations are anyhow very similar, the only noticeable difference is the presence of spines, while flowers, tubercles and size are identical.

Tubercles

Divergent, often flaccid and not erect, not crowded or basally compressed, acute at the apices, flattened adaxially, not fissured, not incurved, 3-7cm long, 5-10 mm broad, more than 4 times as long as wide;

Flowers

3.5-4.2cm in diameter, 2-5 cm long; outer perianth segments magenta with greenish-white margins, inner perianth parts deep magenta, pistil 2-3mm above the stamens; style white 1-2 cm long; stigmaswith 5-8 lobes 1-2,5 mm long;

Spines

None or up to 3, 2-6 mm long, creamy-white.

Stem

Greenish-brown sub-globose, flattened on top, 2-6 cm high, rising barely above ground level, 4-8 cm in diameter.The rest of the plant (swollen rootstock) stay underground.

Fruits

Pinkish-red to reddish purple, globose to elongate, 10-20 mm long, 5-12 mm in diameter.

Areoles

5-12mm from the tips of the tubercles, rounded, 2-5 mm in diameter;