Xerophyte

Central Spines

2-4 similar to radials but stronger (two of which noticeably longer), up to 3 cm long.

Seeds

About 1.2 mm long, 0.9 mm wide, 0.6 mm thick, ovoid to helmet shaped, keeled on the back, black, shiny, finely dotted; hilum more or less oblique.

Note

'chacoanus -a -um' for the occurrence in the Chaco (annually flooded flatlands) of Argentina, extending into Paraguay and Bolivia.

Flowers

Bilaterally symmetrical 55-65 mm long. Nectar-chamber 6-8 mm long, 3-4 mm wide. Tube almost cylindrical 5-7 mm in diameter, ca. 3 cm long, slightly or sharply bent upwards just above the ovary, dependending on position of the stem, reddish brown. Ovary and tube with bright scales and small white hairs in the axils. Corolla 7-12 mm wide very oblique, bent downward; petals 7-9 mm long, 4-7 mm wide, dark red. Filaments white below, and pink to purple above, rows, anthers dark lilac, protruding 5-10 mm. Style whitish, stigma lobes 6-8, green, yellow or reddish with him

Spines

Acicular or setiform, quite variable, straight, white, yellowish or blackish, light tipped with dark base.

Ribs

8-12 ribs, slightly crenate (notched), 3-4 mm high.

Stem

Cylindrical, branching basally, rather upright, then arching or creeping, but the tip of the shoot turned upwards (decumbent), green, 0,5-1,5 m tall, 1,5-3 cm thick.

Radial Spines

(6-)10-12(-15), the lowermost thin, 4-12 mm long, the uppermost, if any, more colourful and slightly stronger.

Fruits

Globular or slightly elongated, crimson,1-2 cm in diameter, pulp juicy, white.

Areoles

Almost round, 2-3 mm in diameter, blackish, 5-8 mm apart.