Ferocactus echidne aka Sonora Barrel Cactus

Ferocactus echidne is a small barrel cactus in the Cactaceae family. Its common names include Sonora barrel cactus and traveler's friend. It comes from central and northeastern Mexico, reaching Veracruz. It grows in dry scrub and near tropical deciduous forest. Wild plants root among volcanic rocks and in limestone soils. Some local populations face threats from changes in land use.

Most plants have one stem, though older plants may form several. The stem is round or flattened, and rarely becomes cylindrical. It stands about 0.4–1.1 feet [0.12–0.35 metres] tall, sometimes more. Its usual width is 0.4–0.7 feet [0.12–0.20 metres]. Rare stems reach about 1 foot [0.30 metres] across. Stem colour ranges from yellow-green to dull grey-green. Between 13 and 21 sharp ribs run along the body. Young areoles feel velvety and have a yellow tint. Each bears one central spine and seven to nine radial spines. The yellow to amber spines turn grey-brown with age.

Yellow or greenish-yellow flowers open near the stem's top. Their funnel shape contrasts with the round, ribbed body. Flowering runs from late spring into summer. In the wild, blooms appear from May through August. With good care, plants can flower while still quite small. Fleshy fruits are round to egg-shaped and retain dried flower parts. They may be pale green, white with pink, or red. Each holds many smooth seeds, dark red-brown to black.

This slow-growing cactus suits pots and growers new to cacti. Most growth takes place during summer. Use a rich mix that drains well, with little organic matter. Water during active growth, then let the mix dry. Never leave the pot standing in water. Excess moisture can cause rot. Reduce watering as autumn approaches and growth slows. Keep water off the stem when it sits in sunlight. LLIFLE links this wetting to scars and fungal damage.

A cool winter rest helps the plant produce more flowers. Dormant plants may survive brief cold spells near −5°C. Even so, winter temperatures above 5°C offer safer growing conditions. Repot in spring when roots become crowded, using a draining pot. Wait at least a week before watering after repotting. Feed during summer only when needed; avoid feeding from September onward. Grow new plants from seed. Give seedlings less intense light and avoid prolonged dryness.