Ferocactus alamosanus aka Alamos Barrel Cactus

Ferocactus alamosanus is a small barrel cactus in the cactus family. Kew places its native range in northern and western Mexico. LLIFLE gives a narrower range around Álamos in southeastern Sonora. This lies along the western edge of the Sierra Madre Occidental. Its account also names nearby parts of Chihuahua and Sinaloa. The cactus grows at elevations of 1,476–4,265 feet [450–1,300 metres]. Kew links it with deserts and dry shrubland. LLIFLE also records tropical forests that shed their leaves and pine-oak forests.

The plant has a round body and a compact form. It usually grows alone, though some plants form clumps. The stem can look like a flattened ball or short cylinder. LLIFLE gives a usual upper height of about 0.82 feet [0.25 metres]. Stem width reaches about 0.98 feet [0.30 metres]. Some plants grow much taller, but the species account gives no firm maximum. Between 12 and 20 narrow, sharp-edged ribs run along the stem. Its small size and round outline suit use as a specimen plant.

Needle-like spines overlap in a dense mesh across the ribs. New spine growth can have a red tint. Each spine group has eight straw-coloured spines around the outside. These measure about 0.10–0.13 feet [0.03–0.04 metres] long. A single central spine can reach 0.20 feet [0.06 metres]. This central spine sometimes has a flat shape. LLIFLE describes the spines as finer than those of some related barrel cacti. It also notes that large plants can be hard to find in cultivation.

Chicago Botanic Garden lists yellow flowers from March to April. LLIFLE describes their colour as yellow with a green tint. The flowers open wide and have broad, spoon-shaped petals. They reach about 0.15 feet [0.045 metres] in length. Their width reaches about 0.11 feet [0.035 metres]. The fruit has a muted brown-red colour. Ripe fruit splits open rather than staying whole.

Chicago Botanic Garden lists both full sun and partial shade. It specifies dry soil and USDA hardiness zones 9–11. Its landscape entry recommends the cactus as a specimen plant. LLIFLE reports a small native range with fewer than ten known locations. That account raises conservation concerns but gives no formal IUCN category.