Ferocactus robustus

Ferocactus robustus, called clump barrel, belongs to the cactus family. It grows wild in Puebla and Oaxaca, Mexico. Its home includes desert and dry scrub, often on plains. This evergreen succulent forms broad mounds of small barrel-shaped stems. Habitat loss has caused a decline in its limited range. Useful Tropical Plants reports a Vulnerable IUCN assessment from 2017.

Reported heights range from about 2.3–3.3 feet (0.7–1 metre). Clumps spread about 9.8 feet (3 metres) across. Large colonies can reach 16.4 feet (5 metres) wide. A mound may hold hundreds of stems. Some may come from seedlings growing near the parent. Each round or club-shaped stem has a smooth, shiny surface. Stem colours range from dark green to reddish grey. Most measure 0.26–0.52 feet (0.08–0.16 metres) across. Each stem has up to eight sharp, raised ribs. Widely spaced areoles carry white felt, which fades with age.

Each areole bears four to six stout central spines. These may be brown, reddish, or horn-coloured. The longest reach about 0.2 feet (0.06 metres). Around ten to fourteen thinner spines surround them. The upper ones tend to be paler and bristle-like. Yellow to orange-yellow flowers appear in spring and autumn. Each measures about 0.10–0.13 feet (0.03–0.04 metres) across. Outer flower segments have a red stripe down the middle. Bees pollinate the flowers. Yellow fruits carry broad, fleshy scales and contain small black seeds.

Grow this cactus in full sun throughout the year. It needs rich soil that drains well. Growth starts slowly, but plants do well in cultivation. Give ample water during the summer growth period. Keep the stems dry when sun falls on them. LLIFLE links wet, sunlit stems with burns and lasting scars. Fungal infection may follow and can kill the plant. Keep it wholly dry in winter, ideally near 10°C. It can withstand brief light frosts down to about -6°C. Growers can raise new plants from seeds or offsets.

Its broad, spiny mounds give it value as an ornamental. The plant also has recorded food uses. Crushed stem pulp yields fluid used as an emergency drink. The source describes its texture and taste as unpleasant. It reports no known hazards or medicinal uses. That does not establish safety for people or pets. Species-specific evidence does not confirm edible flowers, buds, or seeds.