The Arizona Hedgehog Cactus:
Endangered Species or Not?

Background:

In 1979 the Arizona Hedgehog cactus (Echinocereus triglochidiatus var. arizonicus) was listed as an endangered species under the federal Endangered Species Act. It was listed as endangered because people were collecting the plant in the field for landscaping and horticulture. There is also a lot of open-pit mining activity within its range. The Arizona Hedgehog is a beautiful cactus, its stems deep green with large, deep red flowers. It was first discovered and described in the mid-1800's in the mountains and canyons between Globe and Superior, Arizona. This location is considered to be the Arizona Hedgehog's type locality. The cacti growing in this location are considered to be definitive of this variety of cactus. All other cactus populations found growing in other areas which are thought to be Arizona Hedgehog, are compared to the cacti growing at the type locality.

Currently, there is a controversy surrounding the classification of this cactus. There are many other populations of similar cacti growing in the mountains of the southwestern United States and in northern Mexico which are very closely related to the Arizona Hedgehog ("arizonicus"). Up until the mid-1980's it was thought that there were eight different varieties of the species Echinocereus triglochidiatus, one of which was arizonicus. The other varieties had the same flower shape, color and development (called a "claret-cup" flower because it is shaped like a claret wine goblet) but have different spine, stem and rib characteristics. It was assumed that all of the varieties were able to interbreed with one another because there are many populations that appear to be intermediate between two neighboring varieties. This makes identifying the cacti in the field very difficult and confusing.

Recently, some botanists have stated that the populations of hedgehog cactus growing in the mountains of Cochise county, Arizona, and SE New Mexico are the same as arizonicus. These populations have been called E. triglochidiatus var. neomexicanus in the past. The Cochise county cacti are thought to be the same as arizonicus because they are "robust" (large stems) and the diameter of their spines is large ("thick-spined"). If these populations are indeed the same as arizonicus, then the Arizona Hedgehog would be considered widespread and not endangered. A paper published in 1989 (D. J. Ferguson, Cactus and Succulent Journal 61:217-224) says:

"This variety [arizonicus] is nearly collected out at the type locality,
but is common elsewhere. This name was based upon plants of the
robust, thick-spined type common in SE Arizona and SW New Mexico.
This variety has traditionally been interpreted as including only those
plants from the type locality, but this type of plant is in reality quite
widespread."

Because of opinions like the one mentioned above, officials at the US Fish and Wildlife Service have become unsure of the validity of the classification of arizonicus and its range as being limited to the region around the type locality.

"The cloud surrounding the definition of the species has caused
delays and/or lack of interest in providing species protection. The
original description of the species appears to be narrow and does
not represent the true morphological range of the species. A
validation of the species and more refined definition of the taxon
would support and increase protection efforts by helping scientists
and managers identify the plant in the field and would increase its
management profile."

At this point in time, there are three varieties of the species Echinocereus triglochidiatus. The three varieties of E. triglochidiatus are called triglochidiatus, mojavensis and arizonicus. The identity of the Cochise county cacti is unclear. Whether they are similar enough to the arizonicus cacti at the type locality to be called arizonicus remains to be determined. If they are not similar enough to arizonicus, then they are a new variety of the species which has yet to be named or fully described.

The research question:

Are the cactus populations in the Cochise county mountains the same as variety arizonicus? Or, is arizonicus really limited to the mountains and canyons between Superior and Globe, Arizona?