Echinocactus grusonii

Echinocactus grusonii.

Family Cactaceae > Subfamily Cactoideae > Tribe Cacteae.
This is one of the 2 genera commonly known as Barrel cacti.
Echinocactus has around 5 species of very spiny plants.
They have small yellow or pink flowers and hairy fruit.
Some are grown as ornamentals of which E. grusonii is the best known.

E. grusonii, the Golden Barrel cactus, up to around 1 m high, is from Mexico.
Young spherical plants have a knobbly appearance.
They later develop up to 35 or 40 ribs with slightly scalloped edges.
Older plants develop a cylindrical base and the rib edges loose the scallops.
They can be up to 80 cm across.

The vertical areoles on the rib edges are closely spaced.
They have short, woolly, pale yellowish hairs.
Each areole has around 6 spines of different lengths with the longest up to 5 cm.
Spines are straight or slightly curved and a brownish-yellow or sometimes white.
The circular crown is completely covered in woolly, mostly whitish hairs.

Plants may flower after about 20 years.
A ring of flowers develop in a circle near the edge of the woolly crown.
They are funnel-shaped with a 5 cm long, very scaly tube.
The yellow tepal lobes have brown tips.
The fruit have a large tuft of white hairs at the base and shiny, reddish-brown seeds.

There is a form that has no spines.