Trifolium andinum

Trifolium andinum Nuttall was named in 1838. Two varieties were named within Trifolium andinum Nuttall in 1989 (Barneby 1989), T. andinum var. podocephalum Barneby is endemic to eastern Nevada (Barneby 1989). In the 1990s and early 2000s, the other plants within this species (in Arizona, Utah, Colorado, and Wyoming) were considered to be T. andinum var. andinum (Barneby 1989, Isley 1998). In 1998, Isley recognized these two varieties and noted, "The isolated populations of Trifolium andinum are all slightly different one from the other. The level of peduncle development is various, and one may also see peduncled heads (sometimes both of these in a capitulum) northeast of the peripheral Nevada montane locales" (Isley 1998). In 2008, three more varieties endemic to Utah (and the Navajo Nation within Utah), were named; T. andinum var. navajoense S. L. Welsh & N. D. Atwood, endemic to the Navajo Nation within San Juan County, in southeastern Utah, T. andinum var. wahwahense S. L. Welsh & N. D. Atwood, endemic to the Wah Wah Mountains in Beaver County in western Utah, and T. andinum var. canone S. L. Welsh & N. D. Atwood, endemic to the Canyon Mountains of Millard County, in central Utah (Alexander 2016, Welsh et al. 2008, Welsh et al. 2015). If these varieties are recognized, then T. andinum var. andinum is the only variety present in the Uinta Mountains of northeastern Utah, and in the Green River Basin of northwestern Colorado and southwestern Wyoming, where there are many documented locations (Fertig et al. 1998, Welsh et al. 2015). There are plants known from Cococino County, Arizona and a few other locations in Utah which have been identified as T. andinum, and to T. andinum var. andinum. This plant is not known from New Mexico (SEINet 2021).

This species is known from the Green River Basin of southwestern Wyoming and northwestern Colorado, and isolated mountain ranges of the Great Basin in Utah, northwestern Arizona, and eastern Nevada. There are at least 200 locations documented, but the number of occurrences is unknown. Threat impact is uncertain, but likely is high to medium, threats include mining, grazing, and invasive species.

Trifolium andinum is known from the Great Basin of the western United States. It occurs in various isolated mountain ranges in eastern Nevada and Utah, the Grand Canyon area of northwestern Arizona, and in the Green River Basin of southwestern Wyoming, and northwestern Colorado. The range extent is estimated to be 275,000 square kilometers. It has been mistakenly reported from New Mexico. T. andinum var. podocephalum is known only from eastern Nevada (NatureServe 2021, SEINet 2021). In Colorado and Wyoming, only Trifolium andinum var. andinum is known (Ackerfield 2012, SEINet 2021), three other varieties are known from isolated mountain ranges in Utah (Alexander 2016, Welsh et al. 2008, Welsh et al. 2015).

There estimated to be more than 200 occurrences of Trifolium andinum, it is most common in the Green River Basin of southwestern Wyoming, but elsewhere it mainly occurs in isolated mountain ranges (Fertig et al. 1998, NatureServe 2021, SEINet 2021). Isely described T. andinum in general as a "little-collected clover" (Isley 1998).

Occurrences of Intermountain Clover are not reported to be threatened within the Dinosaur National Monument, in Colorado (Colorado Natural Heritage Program 2014). Threats to Intermountain Clover likely include grazing impacts (including from cattle, wild horses, and introduced mountain goats in Utah), recreation impacts (such as from hikers and off road vehicles), mining, road construction, drought, and invasive exotic plants, especially cheatgrass (NatureServe 2021, SEINet 2021, Utah Division of Wildlife Resources 2018). One of the known populations is very close to a large weed infestation (NatureServe 2021). Threat impact is uncertain (Alexander 2016), but likely is high to medium.