Ivesia arizonica

Kartesz (1999) lists Purpusia saxosa as a synonym of Ivesia arizonica var. saxosa. According to Jim Morefield and Barbara Ertter, when the species Purpusia saxosa was transferred to Ivesia, the name Ivesia saxosa was already in use for a different species, so the species had to be called by the next available name, Ivesia arizonica. When the variety saxosa was recognized, some people erroneously assumed that it included all the former reports of Purpusia saxosa. Instead, all reports of Purpusia saxosa from outside Nevada were based on specimens of what is now recognized as Ivesia arizonica var. arizonica, which was formerly included in Purpusia saxosa by some authors.

Var. saxosa is endemic to southern Nevada (Nye and Lincoln cos.) with only 5 known occurrences; threats unknown. Var. arizonica is more abundant and widespread, known from se. California, s. Nevada, sw. Utah, and nw. Arizona. Although it is not common, those familiar with the typical variety believe that there are sufficient populations in Nevada and Arizona with no imminent threats that it is reasonably well off, especially since it generally occurs on remote cliffs out of reach of grazers and many human disturbances. Two extant occurrences are known from California and only a few are estimated in Utah. More populations of var. arizonica may be found with additional searching, particularly in Arizona.

var. saxosa is endemic to s. Nevada (Pahroc and Sheep ranges; Pahute Mesa), in Nye, Lincoln, and possibly Clark counties. var. arizonica is more widespread, occurring in se. California (Grapevine and Funeral mts. of Inyo Co.), s. Nevada (Silver Peak Range, Esmeralda Co.; Shoshone Mt., Belted Range, amd Grant Range of Nye Co.; Meadow Valley Wash of Lincoln Co.), sw. Utah (Kolob Plateau, Washington Co.), and nw. Arizona (both sides of the Grand Canyon, Mohave and Coconino cos.) (Cronquist et al. 1997).

var. saxosa in endemic to Nevada with 5 known occurrences. For var. arizonica, Barbara Ertter (pers. comm. to R. Bittman 2008) states that, "while it is certainly not a common [taxon], there are sufficient populations in southern Nevada and northern Arizona with no imminent threats that it is reasonably well off, especially since it generally occurs on remote cliffs (high probability of additional undiscovered populations)." Estimated rank is S2S3 in Nevada (which typically corresponds to 6 - 80 occurrences). In Arizona, there is believed to be plenty of potential habitat in the Grand Canyon, but it is unknown how widely distributed it is there, as the taxon has not been thoroughly searched for (30 AZ specimens found on SEINet in 2008). In California, known from two extant occurrences (verified 2000 and 2001) and two historical occurrences (collections from the 1930s). Considered critically imperiled (S1) in Utah, likely with few occurrences.

For var. arizonica, many populations appear to have no imminent threats, as it generally occurs on remote cliffs out of reach of grazers and human disturbance. Threats to var. saxosa unknown.