Echinocactus grusonii

Golden barrel, mother-in-law's seat
Bright golden spines that emphasize its distinctive barrel shape make this beautiful species ideal as a feature specimen. Pot-grown plants take 30-40 years to reach a flowering size of about 38 cm (15 in) in diameter. Small, funnel-shaped, summer blooms are followed by papery seed pods. Keep the plant warm and dry in winter.
H 1.2 m (4 ft), s 3 m (10 ft). Min 10°C (50°F).

Echinocactus horizonthalonius

Is the smallest representative of the genus, adult specimens attaining 15 to 20 cm in diameter, and usually remaining disc-shaped. Unlike the previous species, it is difficult to grow. It requires a loam-based potting mix, maximum warmth and sunlight and minimal watering. This applies mainly to seedlings which are slow-growing but grow faster after grafting. Nurseries occasionally stock specimens which can be grown successfully. They flower on hot summer days, throughout the season. This cactus is distributed throughout the Chihuahua Desert, from San Luis Potosí up to the south of New Mexico and Texas.