Growth habits: The plant is fairly slow growing, but eventually it forms a clump, each individual body up to 1.6 inches in diameter (4 cm). The epidermis is pruinose (has a bloom or powdery covering), this is easily washed off if care is not taken when watering. The spines can either be white with black tips or completely black. There are normally seven to eight radials and one central spine. The body has raised nipples, not unlike Mammillaria and the areoles are felted. Ortegocactus is a monotypic [having only one species] genus.
Scientific name: Ortegocactus macdougallii
Common names: Unaware of any common names.
Synonym: Neobesseya macdougallii
Etymology: Ortegocactus: in honour of the family Ortega de San Jose Lachiguire which, according to original description, helped Tom MacDougall in the discovery of this plant (and not in honour of the Mexican botanist Jesús Gonzáles Ortego (1876-1936) as one sometimes sees it).
macdougallii: in honour of Tom MacDougall who discovered the plant at the beginning of the Fifties and brought it to Edward J. Alexander.
Origin: Mexico (Oaxaca) on limestone rocks
Light: The plant will accept full sun, but I find mine does just as well in light shade.
Compost: The plant likes an extremely free draining mineral compost. The addition of limestone chippings if available is very beneficial.
Water: This plant is very prone to rotting and should be kept in a ‘half’ or shallow pot and watered with great care. As an old plantsman used to say, just show it the watering can.
Flower: The plant has yellow flowers up to 2in. in diameter in the Spring.
Fruit: It is a self-fertilizing plant. The fruit is spherical and woolly. The seeds are almost round
Min. temp: Most of the books recommend a minimum temperature of 60°F. (15°C.) but I must admit I keep mine at a lower winter temperature than that.
Cultivation: A plant that does need special treatment and cannot be lumped in with all the other plants in a collection. The ‘general’ watering regime would probably kill the plant in a reasonably short space of time. Also a mineral compost with the addition of limestone is almost essential. The plant has a nasty habit as it gets older of forming ‘rust’ spots on the epidermis. These are not detrimental to the plant but can spoil its appearance.
Habitat: The plant is only found in Oxaca, Mexico, growing amongst limestone rocks. They are found at an altitude of between 2,500 and 2.700 metres and are exposed to the sun.
Comments: Not one of the easiest plants to find (certainly in England) and definitely not one of the easiest to grow successfully. To anyone who does not know the genus the colour of the plant would suggest that it is not in the best of health. However this is the true colour of the plant, almost a lime green and quite unusual in cacti.