Ferocactus viridescens
Ferocactus viridescens is a species of flowering plant in the cactus family Cactaceae. This barrel cactus is known by several common names, including coast barrel cactus, keg cactus and San Diego barrel cactus. Most of its native range in the United States is in San Diego County, California, where it is threatened by development, agriculture, and other alterations in its habitat. It is also found in northern Baja California, Mexico.
Description
Ferocactus viridescens is a solitary barrel cactus, typically spherical, oblate, or nearly cylindrical, reaching heights of 10-30cm and diameters of 10-20cm. It has bright green flesh arranged into several 13 to 34 blunt ribs covered in arrays of long spines. The areoles are narrow elliptic to oval, long, with brownish tomentum, bearing 10-19 spines per areole, including central and radial spines. The central spines are initially pink or yellowish, becoming duller with age, with the principal central spine measuring long and 2-3 mm broad. The 10-20 radial spines are similar to the centrals but smaller, long.Blooming from spring to early summer, the species produces infundibuliform flowers that are long and in diameter, with greenish-yellow or greenish perianth segments sometimes tinged with pink. The flower tube bears stamens almost to the top of the ovary, with yellow stigma lobes. The fruits are barrel-like, bright yellow, with a pleasant acid taste, measuring long and across. They have a leathery skin and about 30 fimbriate-denticulate scales, dehiscent through a basal pore. The seeds are elongate-obovoid, minutely reticulate, and measure long.
Taxonomy
Taxonomic history
Ferocactus viridescens was first discovered in 1836 by Thomas Nuttall, an English botanist and naturalist. Nuttall had arrived in San Diego aboard the hide ship Pilgrim, and stayed in the harbor for three weeks while he waited for a Bryant and Sturgis ship to sail him back to Boston. From Nuttall's specimens, John Torrey and Asa Gray described Echinocactus viridescens in 1840. The Latin specific epithet viridescens means "turning green". Nathaniel Lord Britton and Joseph Nelson Rose later reclassified the species under the genus Ferocactus in 1922, creating the current combination.Infrataxa
Some authors recognize infraspecific taxa for this species, but vary in their recognition of the rank.- Ferocactus viridescens var. littoralis G.E. Linds. – It is also infraspecifically recognized at subspecies rank as subsp. littoralis F. & R. Wolf. Commonly known as the Santo Tomás coast barrel cactus. A variety endemic to Baja California, first collected by Reid Moran at Santo Tomás. Compared to the typical variety, var. littoralis is characterized by a more golden hue, a taller size, and a higher number of ribs and central spines. This variety is occurs from north of Ensenada south to the vicinity of Misión [Santo Domingo de la Frontera].
Distribution and habitat
Its preferred habitat varies, as it inhabits elevations ranging from sea level to 200 meters, in coastal, mild-winter microclimates as well as warmer, inland areas that may experience autumn or winter frosts. It grows in sandy and gravelly soils with a generally high mineral content.
Habitats where Ferocactus viridescens may be found include chaparral, arid hills, dry and grassy dunes, or rocky coastal bluffs and sun-baked cliffs; cacti especially thrive along the Californian and Mexican west coasts, as they experience significant fog cover throughout the year, notably in the mornings and evenings, allowing the plants to absorb sufficient moisture before the heat of the day. This habitat also gives Ferocactus viridescens an innate tolerance for salts and minerals that many botanical species simply cannot handle. The San Diego barrel cactus can also be found on shrub-covered hillsides, often at the crests of slopes, and in cobbles. Occasionally, it is found on the edges of vernal pools, sometimes in large numbers. This habitat, which is more moist compared to its usual xeric shrublands|xeric] environment, is unusual for the plant, and may occur sporadically during years of excessive precipitation in the area.