Photo of Malacothamnus jonesii


For my PhD research at California Botanic Garden, I studied the genus Malacothamnus (Malvaceae), commonly known as the bushmallows, which has several conflicting taxonomic treatments and many rare taxa. I used a combination of morphometric analyses, Restriction site Associated DNA Sequencing (RAD-Seq), comparative phenology, and extensive field evaluations to clarify taxon boundaries within the genus and evaluate the conservation status of each taxon. The end result of this is a three-volume open-access monograph on the genus. Most people will only be interested in the third volume, which includes a new treatment of the genus and conservation assessments. For those who want to dig deeper, the first two volumes go into the details of the evidence used in making the taxonomic decisions for the treatment. Summaries and links for each volume follow:

Image of 3-volume Malacothamnus monograph

Malacothamnus Volume 1 is a morphological assessment of Malacothamnus to clarify how morphologically distinct previously described taxa and possible undescribed taxa are. These analyses resulted in specimen groupings with varying degrees of morphological and geographic cohesion, most of which align with previously described taxa.

Malacothamnus Volume 2 uses phylogenetic analyses to test the morphological groupings from Volume 1 as hypothesized lineages. The resulting evidence from both morphological and phylogenetic analyses are then used to make taxonomic decisions for the treatment in Volume 3. Areas where further research is needed are noted and three new species are described.

Malacothamnus Volume 3 is a new treatment of Malacothamnus, which includes preliminary conservation assessments of each taxon and natural history information related to the genus. It also summarizes some of the findings in Volumes 1 and 2 for those who do not wish to delve into the details in those volumes.

Videos: For a video summary of this research, you can watch my 2020 presentation for the Southern California Botanists Symposium here and/or my 2022 PhD dissertation defense here. The 2020 presentation may be a better starting place if you don’t know much about Malacothamnus but the 2022 presentation has more up to date information, though that is a bit out of date relative to the monograph.

Additional Publications:

A morphological assessment of the Malacothamnus palmeri complex (Malvaceae) – Jan. 2021

Malacothamnus enigmaticus (Malvaceae), a new rare species from the desert edge of the Peninsular Range in San Diego County, CA – Oct. 2019