Xerophyte

Central Spines

4-6 brown, redish or horn-coloured coloured, erect, radiating, straight, annulate, square or angled in cross section, sometimes flattened laterally, the lower one longer up to 6 cm long.

Seeds

Black 1,5 mm long and 1 mm wide, finely sculptured with polygonal ridges.

Description

Clumping small barrel cactus, that forms powerful colonies of hundreds of branches, reaching over 90-100 cm high and 3(-5) m wide. The remarkable polycephalic habit of Ferocactus robustusSN|21488]]SN|21488]] is quite unlike that of any other species in the genus. These clusters are probably not from the same original root system, but are a complex which has developed from seedling plants which have grown up around the parent.

Flowers

Yellow to yellow-orange, 3-4 cm in long and in diameter. Ovary covered with broad, rounded imbricated scales, these intergrading into the outer perianth segments; outer perianth segments yellow with red midstripe, mucronate; inner perianth segments yellow, oblong, acute; stigma lobes 10, red.

Blooming Season

Spring and autumn .the blossoming period is long.

Ribs

Up to 8., prominent, acute, thickened under areoles, tuberculate.

Stem

The individual stem are some of the smallest of the genus, globular to clavate, smooth, shiny dark green to red-grey, 8 to 16 cm wide (rarely exceed 20 cm of diameter).

Radial Spines

Needle-like, approx 10-14 , the lower ones much like the centrals and the upper ones acicular or bristle-like and lighter in colour.

Fruits

20-30 mm tall, 20 mm in diameter, yellow, with broad, widely separated, fleshy scales.

Areoles

Few and widely separated on the ribs, approx 8 mm in diameter in diameter, with an upper flowering portion, whit short dull white felt, becoming inconspicuous in age.