Plains Cactus ( Pediocactus simpsonii )
By George Olin
This spiny little plant is a maverick among cacti—it ranges far out of the desert and it varies so greatly in appearance that specimens might often be mistaken for different species. It not only thrives where rainfall is plentiful but seems to prefer a cold winter climate with snow in which to go through its dormant period. Its distribution, according to Britton and Rose, is “Kansas to New Mexico, north to Nevada, Washington, Idaho, and Montana.” Bailey locates it in Colorado, Wyoming, Utah and Nevada. Originally grouped with Echinocactus by Engelmann, Britton and Rose later created the genus Pediocactus for this single species. Its present name, from the Greek meaning Plains Cactus, is descriptive
of its habit of growth. Although nearly always found in more or less level stretches of stony plateaus of semiarid western states, it is occasionally found in isolated clumps among the conifers at high altitudes.
It is becoming increasingly difficult to find perfect specimens, for much of its range is used as grazing ground for sheep, and their sharp hoofs
mutilate the smaller plants. One’s first impression of the Plains cactus is—”What a sticky looking plant!” The low globular body seems crowded with spines extending at every angle. Closer study reveals that the spines rise from tubercles which ascend in spiral
rows from the base. Each tubercle has from 12 to 20 radial spines which are usually white. The central spines number from 5 to 7 and are much stouter and longer than the radials. In color they vary from white at the base and reddish brown at the tips to an almost
jet black form found in Washington. The flowers are up to 1 inch in diameter
and rise from near the tip of the plant. They are surrounded at the base
by a brownish white wool.
The color of the flower varies a great deal—it ranges from a light shade of yellow to a rich pink. The stamens are a bright yellow and the style is a paler shade of yellow sometimes slightly tinged with green. The flowers open during the late forenoon and last for several days. At night they will close almost entirely and then open again on the following day.
It should be borne in mind when trying to identify this plant that it is one of the most variable in its characteristics of any of our northern cacti. The plants near the eastern portion of the range are almost always solitary and quite small— from 2 to 5 inches in diameter and 1 to 3 inches in height. The spines are light in color and comparatively weak. As they work westward the plants become more robust and those found in Washington may form clumps up to a foot in diameter and 6 inches high. The spines darken to a deep shining brown color and in some cases plants with black spines have been found.
Favorite cactus blossom of J. Smeaton Chase is that of Echinocereus engelmannii
which he described in his “California Desert Trails”: “The plant looks like
a colony of a dozen or so spiny cucumbers, set up on end, generally under the
shade of a creosote bush or in the lee of a boulder. I have no grudge against
this fellow, who bites only if you strike him. The blossom is a most charming
one, a sheeny, rose-like cup of superb purple or wine color, crowded with golden-
anthered stamens and with a pistil breaking into soft green plumes that curl
as daintily as a moth’s antennae.”