• ETYMOLOGY
Genus honouring Hermann Auguste Jacques Gruson (1821-1895), German collector of cacti of French origin (see portrait above, public domain). • DESCRIPTION
Monospecific genus of plants forming impenetrable dense clumps, with segmented stems, with tuberculate low ribs, areoles with white felt. Glochids absent on adult plants. Spines without sheath, aciculate to slightly flattened. Leaves tiny, linear, soon deciduous.
Flowers diurnal, self-sterile, subapical, yellow, pollinated by insects. Fruits ellipsoid, strongly umbilicate, with unpleasant taste. Seeds (about 50 per fruit) discoid strongly compressed, pale yellow. • HABITAT
The monotypic genus Grusonia grows endemically in very large colonies between 1200 m and 2000 m in altitude, in the valleys of the Sierra de la Paila (Coahuila, Mexico), in a basin (depression of Mapimi) and in the state of Durango, among bushes and grasses, on limestone rocks and some basaltic volcanic areas, together with other cacti (Astrophytum, Ariocarpus, Leuchtenbergia), Agave lechuguilla, and forms sometimes an impenetrable barrier. Soils are poor in organic material. In winter, the temperature can drop down to -8°C. • DISTRIBUTION
Mexico (Coahuila, Durango).
Currently only one recognised species:
– Grusonia bradtiana* (J.M.Coult.) Britton & Rose 1919
• ETYMOLOGY
Cactus with glands, because plants in the genus have nectariferous glands. • DESCRIPTION
A genus of usually solitary plants (except when the apex has been damaged), globose to cylindrical, with bluish-green
epidermis, with fusiform (spindle-shaped) roots. Ribs strongly tuberculate, wavy and furrowed. Central spine hooked, often very long.
Flowers diurnal, borne on the areolar groove, funnel-shaped, brown red to almost black, pollinated by insects. Fruits egg-shaped, juicy, indehiscent, green to reddish. Seeds comma-shaped, brown, rough, shiny. • HABITAT
The genus Glandulicactus grows between the southeast of United States and the northeast of Mexico, in the Chihuahan desert, especially on both sides of the Rio Grande, among grasses, usually at the foot and in the shade of xerophyllous shrubs, in arid regions, on well drained or rocky alluvial, limestone, sandy, gravelly soils, on hills, in crevices of cliffs, from 800 m up to 2300 m in altitude. However, these soils remain relatively humid after the sudden summer showers. The populations are usually rare and scattered, but have a wide distribution. • DISTRIBUTION
Mexico (Chihuaha, Coahuila, Durango, Guanajuato, Nuevo Leon, Queretaro, San Luis Potosi, Sonora, Tamaulipas, Zacatecas), USA (New Mexico, Texas). Currently 2 recognised species + one subspecies:
– Glandulicactus crassihamatus* (F.A.C.Weber) Backeb. 1940
– Glandulicactus uncinatus* (Galeotti) Backeb. 1939
– Glandulicactus uncinatus subsp. wrightii (Engelmann) U.Guzman 2003
• ETYMOLOGY
Genus honouring George Sebastian Hinton (1949-), Mexican botanist who discovered the taxon (see portrait above, ccourtesy of George S. Hinton). • DESCRIPTION
Monospecific genus of solitary plants (except when the apex has been damaged), globose to subglobose, becoming columnar with age, with bluish-green epidermis. Deep and well-defined ribs, not tuberculate. Areoles at first woolly at the apex, becoming glabrous with age. Spines few (0-3), slightly curved, more or less papery, soon deciduous.
Flowers diurnal, self-sterile, apical, funnel-shaped, intense pink to magenta. Fruits hidden in the apical wool, naked, with irregular dehiscence, floral remains persistent. Seeds small, rough, black, shiny. • HABITAT
The monotypic genus Geohintonia grows in very large colonies, but in a limited area, in the state of Nuevo-Leon in Mexico, together with Aztekium hintonii and other cacti and succulents, at approximately 1200 m in altitude, on steep hills or cliffs of pure gypsum. • DISTRIBUTION
Mexico (Nuevo-Leon).
Currently only one recognised species:
– Geohintonia mexicana* Glass & Fitz Maurice 1991
• ETYMOLOGY
Genus honouring Manuel Fraile (1850-?), born in Spain, responsible for the cactus collection of the Department of Agriculture of the United States in the late nineteenth century. Portrait is unknown. • DESCRIPTION
Genus of dwarf plants, usually solitary, also forming clumps of small globose to shortly elongated low stems, with ribs and tubercles little developed but visible. Spines very small, not aggressive.
Flowers diurnal, self-fertile, always pale yellow, appearing at the apex of stems, cleistogamous (self-pollinating) or opened for a crossed pollination made by insects, usually bees (Schlindwein & Wittmann 1995, in Emerson 2007), with a floral tube densely woolly and setose. Fruits with floral remains persistent, thin-walled, with irregular dehiscence or indehiscent, full of seeds. Seeds shiny, helmet-shaped or ovals, brown to blackish brown, finely papillose, of various size according to the species, floating, dispersed by rainwater (hydrochory). • HABITAT
The genus Frailea has an extensive geographic range, and usually grows in the shade of shrubs, among grasses, but also in sunny places, at ground level, in plains, on rocky or sandy soils, gravels, rocky outcrops, in pockets of fine sand, between mosses and lichens, sometimes together with fungi (F. cataphracta), from 20 m up to 900 m in altitude, often with other cacti (Notocactus, Echinopsis, Opuntia). Plants tend to bury themselves and disappear almost completely into the soil during the dry season. • DISTRIBUTION
Argentina (Corrientes, Entre Rios, Misiones, Santa Fe), Bolivia (Santa Cruz, Tarija), Brazil (Mato Grosso do Sul, Rio Grande do Sul), Colombia (Dagua)? (never found again), Paraguay (Alto Paraguay, Asuncion D.C., Boqueron, Concepcion, Cordillera, Guaira, Itapua, Misiones, Paraguari), Uruguay (Artigas, Cerro Largo, Colonia, Durazno, Flores, Florida, Lavalleja, Maldonado, Paysandu, Rivera, Rocha, Salto, Soriano, Tacuarembo, Treinta y Tres).
• ETYMOLOGY
“Floriferous”, emphasizing the abundant flowering of the genus. • DESCRIPTION
Monotypic genus of shortly columnar shrubby plants, with stems semi erect to decumbent, branching from the base. 13-18 ribs rounded, areoles regularly arranged, felted, but becoming glabrous with time. Spines short and aciculate.
Flowers diurnal, self-sterile, appearing near the apex, with a floral tube pinkish red, or purple, bearing tiny scales, with whitish tepals, probably pollinated by hummingbirds. Fruits globose, reddish, covered with a bluish wax. Seeds tiny, dark brown, with marginal stripes. • HABITAT
The monotypic genus Floribunda grows endemically in the north-central Minas Gerais in Brazil, between 800 m and 1000 m in altitude, on the western hillside of Serra Geral, in the campo rupestre (in Brazil, mountainous subtropical savanna), on cliffs and ledges of crystalline rocks, among shrubby vegetation. This is an extremely rare plant in its habitat. • DISTRIBUTION
Brazil (Minas Gerais).
Currently only one recognised species:
– Floribunda pusilliflora Ritter 1979
