Xerophyte

Central Spines

0-1, pointing upward.

Seeds

Shaped like snail shell, about 1.7 mm long and 1 mm wide.

Roots

Diffuse.

Note

vertongenii For Dr. Herman Vertongen (fl. 1995), Belgian cactus enthusiast.

Flowers

Borne near the apex on young areoles, funnelform, light yellow to salmon, to 4 cm long and in diameter. Tube conical, brown olive, with dark brown scales bearing a blackish mucro (a fine point), trimmed with abundant long fluffy wool and 3-5 black silk-bristles, up to 10 mm long in the upper part of the tube.Outer perianth-segments lanceolate and mucronate, pink salmon with broad median brown line.Inner perianth-segments more broadly lanceolate or spatulate mucronate, light yellow with a pink salmon median line and carmine mucro. Throat and filaments greenish-yellow. Anthers sulphur yellow. Style light pink. Stigma lobes10 white.

Ribs

8-13, clearly separated by vertical furrows forming small rounded chins only in the upper part of the plant. The transverse furrows are short.

Stem

Solitary except in case of injury to the growing tip, flattened to subglobose, greenish-grey to greenish brown, to 3.5 cm tall and 5.5 cm across. Older plants may occasionally grow larger, but without ever exceeding the size of a fist (about 10 cm). Apex slightly depressed, woolly and with spines.

Radial Spines

5-9, in 2-4 lateral pairs with an odd spine directed downwards, stout, round in cross section, needle-like, acuminate, more or less erect, slightly curved, with dark grey to black tips (Completely black in the wet state), short, not more than to 15 mm long .

Fruits

Elongate to barrel-shaped, up to 17 mm high and 14 mm in diameter, tannish to blackish, covered with black-tipped scales with white wool and blackish silky bristles, wind dispersed, dry, dehiscing by basal pores.

Areoles

Oval, relatively large 5-6 mm long and 4-5 mm wide, at first covered with yellowish white wool, becoming dirty white and more or less naked eventually.