Xerophyte

Central Spines

4(-5), crisscrossed, similar to the radials but a little stouter and longer, at most 2,5 cm long, about 1 mm in diameter, thicker at the base (more than 2 mm), the lower one, stronger and noticeably bent toward the apex, dark rose-coloured to black, becoming yellowish-grey.

Note

Eriosyce curvispinaSN|2434]]SN|2434]] subs. tuberisulcata correspond to Pyrrhocactus horridusSN|18409]]SN|18409]] sensu Ritter.tuberisulcatus Lat. 'tuber', tuber, swelling; and Lat. 'sulcatus', furrowed; for the deep furrow separating the tubercles of the ribs.

Flowers

4.5 cm long. Petals carmine with a light yellowish border, areoles on the pericarpel and floral tube sparingly woolly.

Ribs

14-20, prominent, obtuse, strongly tubercled, separated by narrow intervals. Tubercles arranged in weakly spirally rows, at first elongated, sharp, later roundly prominent, with a flattened acute chin-shaped protrusion below the spine cluster. The old tubercles more or less incised with a broad furrow on the lower part separating the tubercles.

Stem

Simple or sometime in clusters of 9 or fewer heads, globular, to flattened spherical, dull-green, depressed and almost spineless at apex, often 20 cm in diameter.

Radial Spines

10-12 strong, compact, cylindrically in cross-section, spreading, white gray to near black, gray in age, often in the upper part of the areoles there are 3, shorter and much finer spines, that are straight, and upright-protruding.

Areoles

At first small, spineless, with an abundance of white wool but when old large. Sometime 1.5 cm in diameter.