Single Record

Counties: Alamosa, Conejos, Costilla, Hinsdale, Mineral, Rio Grande, Saguache

PhotoRecords: YES Rich Haswell: Rio Grande Co, Lookout Mt. by Del Norte 14 June 2017

Comments: Unlike Paronychia pulvinata, P. sessiliflora does not ascend into the alpine. In foothill and montane terrain it is often associated with volcanic substrates, and grows on rocky slopes and rock ledges. Watershed records are all from the west side except for one occurrence along Mosca Creek in Alamosa Co (2022, iNaturalist observation, #122415765). The location of Lookout Mountain near Del Norte (2014-2022), documented with photorecords, would add Rio Grande to counties indicated in Ackerfield (2022) and BONAP (2022). Note the geographically isolated population centered around the San Luis Hills of Costilla and Conejos counties. The earliest collection is from 5 miles west of San Acacio (Costilla Co 1934), followed by a 1986 collection and several 2022 iNaturalist observations from Flat Top (10 km north east of Manassa). This relatively isolated population may include the 2005 collection from the San Luis Hills (Costilla Co) determined by William Weber as "Paronychia pulvinata." (Thanks to Patrick Alexander for pointing out this population, personal communication of Feb 2024.) Of the two nailworts in the Watershed, P. sessiliflora has a much wider range in the USA than S. pulvinata. P. sessiliflora is found in all states west of the Great Plains except for California, Oregon, and Washington, and follows the Rio Grande drainage halfway down New Mexico, to Torrance Co.