Paronychia leucochthonicola (Caryophyllaceae: Paronychieae), a new species of the San Luis Valley, north-central New Mexico and adjacent Colorado.

Paronychia leucochthonicola C.E.V.Alexander sp. nov. is described from two population complexes in the San Luis Valley, one along the Rio Grande Gorge west of Taos (New Mexico), the other centered on Flat Top in the San Luis Hills (Colorado). This is a rare species, occurring in narrow bands of habitat along rimrock. These plants have previously been identified as either Paronychia pulvinata or Paronychia sessiliflora. Paronychia leucochthonicola differs from both in having fringed stipules that conceal the leaves. It is more similar to the alpine Paronychia pulvinata, which is found at high elevations in the surrounding mountains. Additional distinguishing features are discussed and a key to the Paronychia of Colorado, New Mexico, and Wyoming is provided.