Identity
Unique IDELEMENT_GLOBAL.2.1134372
Element CodePDMAL0Q0K0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderMalvales
FamilyMalvaceae
GenusMalacothamnus
Other Common NamesRound-leaved Bush Mallow (EN)
Concept ReferenceSlotta, T. 2012. Malacothamnus, in Jepson Flora Project (eds.) Jepson eFlora Online. Available: http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=9579 (accessed 5 Dec 2019).
Taxonomic CommentsMorse (2023) and Slotta (2012) recognize Malacothamnus orbiculatus and M. fremontii as distinct species. In contrast, Flora of North America (2015) and Kartesz (1994, 1999) included M. orbiculatus in M. fremontii.
Conservation Status
Rank MethodLegacy Rank calculation - Biotics v1
Review Date2020-08-04
Change Date2020-08-04
Edition Date2020-08-04
Edition AuthorsTreher (2019), rev. Carolyn Flower and A. Treher (2020).
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences21 - 300
Rank ReasonsMalacothamnus orbiculatus is a fire-following shrub that occurs in California and Arizona. Threats are unknown but relate to post-fire growth, when competition from non-native species, vegetation treatments including herbicide, and other disruptions to the plants life cycle may occur. Development can unknowingly extirpate sites, as planning surveys may not coincide with recent burns when plants are likely detected. Many occurrences are on National Forest lands. This taxon is not recognized in some treatments, where it is lumped with M. fremontii.
Range Extent CommentsMalacothamnus orbiculatus occurs in California and Arizona. The material in Arizona is tentatively considered M. orbiculatus based on morphology but additional DNA analyses are underway to further confirm its identity (K. Morse, pers. comm., 2020).
Occurrences CommentsThe number of occurrences is unknown but is estimated based on herbarium records and observations made through iNaturalist.org (2020).
Threat Impact CommentsThreats are not well documented. Many occurrences are found on National Forest Land, which affords some protection. Species of Malacothamnus are fire followers which should be surveyed in the immediate years after fire; plants die off as time passes since the last burn. Surveying post fire is important to identify and protect sites. While surveys precede development, they are unlikely to find plants without a recent site burn. Fire suppression is a low-level threat. They generally need fire to germinate, but the seed may lie dormant for 100 or more years and fire is likely to occur within this time interval. Post-fire vegetation treatments are a threat, as they disrupt the species short time frame to live and produce seeds. Grazing, herbicide, mechanical clearing, etc. can reduce or eliminate the seed being produced for the next generation. In addition, abundant non-native species may compete with germinating Malacothamnus the year following the fire. Herbicide after the fire, to control non-native species, may kill both (K. Morse, pers. comm., 2020).