How to identify and how it grows
The Foxtail Cactus grows as a single stem or in clumps. The stems are cylindrical and two or three inches in diameter, with tubercles nearly an inch long and also cylindrical. The whole plant is covered with a dense growth of white radial spines with dark tips, and a group of six to a dozen central spines whitish below, and with the upper half black shading off to a reddish brown. This gives the plant a striking appearance. All of the spines are very stiff. The flowers are straw-colored, about an inch and a half long, and have light pink tips. The petals are lance-shaped and narrow.
How to grow
Plants may be grown out of doors where the temperatures in winter are not lower than fifteen or twenty degrees below freezing, that is 12° to 17° Fahrenheit. In colder climates than this the plants must be protected in winter or grown in sunny, warm conservatories. They may be grown from seed in pots in sandy soil with partial shade and with enough watering to keep the soil moist but not wet. Transplant larger plants in sandy or gravelly soil in bright sunny exposures and give only occasional irrigation during dry periods.
Cream Cactus (Mammillaria MacDougalii)
(Named for Dr. D. T. MacDougal, collector of western plants and Director of the Desert Botanical Laboratory of the Carnegie Institution)
How to identify and how it grows
The Cream Cactus grows from solitary stems or heads, and in many instances in clusters four inches high and six inches in diameter. The tops of the plants are flattened with the centers depressed, or often growing level with the ground. The older plants are much taller and broader. The tubercles are placed spirally and are a half-inch long. If injured they yield a white creamy fluid. There are eleven to thirteen radial spines with one to three centrals whose bases are yellow and bulbous. The spine body is a pale red with brown or purple-brown tips. The flowers are a little more than one inch long and one inch wide, and of cream color to light yellow. The fruit is a deep rose-red and the seeds are reddish purple. This plant likes the gravelly clay loam soils best.
How to grow
These plants can be grown nearly anywhere with temperatures no lower than twenty degrees of frost; but with zero temperatures protection should be given, or the plants grown in rock gardens in sunny conservatories. They grow easily from seed in sandy or gravelly clay loam soil with partial shade and enough irrigation to keep the soil moist. Plants transplant readily to rocky or gravelly clay soils at almost any season, if the thick fleshy roots are not injured in digging. Water moderately once a month, and where convenient set plants among rocks.