How to identify and how it grows
This species grows with solitary stems, only occasionally two to three together, a foot or so high, nearly a foot through and cylindrical. Along the stems run thirteen to seventeen quite prominent ribs covered with coarse tubercles, and a dozen or so two-inch radial spines and one to four central thorns, three to six inches long. These grooved spines are all crooked and twisted, also quite slender and brittle, sometimes breaking or splitting lengthwise. The radials are purplish, the centrals gray or tan. The flowers are three inches long, yellow tinged with tans and reds. The fruit is oblong, sweet, and edible. From it the dried sweetmeats are made.
How to grow
Transplant at any season, preferably in the spring, in sandy or gravelly clay loam in sunny exposures, with enough irrigation to keep the soil moist. The plants grow readily from seed sown in sandy loam in flats with part shade and watered sufficiently to keep the soil lightly moist. They grow inside and out and are uninjured by zero temperature, but with colder weather they should have protection.
Mexican Lime Cactus; Limos de Visnaga (Echinocactus Pringlei—Ferocactus Pringlei)
(Named in honor of C. G. Pringle, botanist and collector of southwestern plants)
How to identify and how it grows
The stems of this species grow singly or occasionally in clumps of a few. They are three to nine feet tall, something over a foot in diameter. Their ribs are quite prominent. The spines form in a marginal fringe of white bristlelike inch-long hairs that are bent and twisted, four to eight radials and four centrals, two inches long or less, cross-ridged and light red and yellow at their bases. The flowers encircle the tips of the stems in an orange-yellow cluster of twenty petals and sepals, each one an inch or so long and broad, and formed like a bell. The fruit is elliptical, orange or red, and is filled with a colorless limelike juice from which delicious lemonade is made; hence the common name, Lime Cactus. The plants thrive in the loamy soil of foothills and mountains in Central Mexico.
How to grow
Set out in spring in loamy soil or sandy loam in a sunny exposure with moderate irrigation. The seed may be sown in June in sandy loam, in flats in part shade and with enough irrigation to keep the soil moist. The plants thrive either out of doors or within and are not injured at twenty-five degrees below freezing; but with zero weather they require some protection.