Keir Morse - Botanist & Photographer

Malacothamnus -The Bushmallows

Malacothamnus jonesii

For my PhD research through California Botanic Garden, I'm studying the genus Malacothamnus (Malvaceae) which has several conflicting taxonomic treatments and many rare taxa. I am using a combination of morphometric analyses, Restriction site Associated DNA Sequencing (RAD-Seq), comparative phenology, and extensive field evaluations to resolve the taxonomy of the genus Malacothamnus and evaluate the conservation status of each taxon. This work will hopefully be completed by the end of 2022 and published in 2023. I hope to fill in this web page with more resources on the genus as I have time.

For an introduction to my 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.

iNaturalist Project

I've created an iNaturalist project to help with this research which you can visit here. iNaturalist users have been a great help in documenting locations, variation, and phenology in the genus Malacothamnus. All observations are welcome. If you want help identifying Malacothamnus, this is a good place to post your observations as I regularly check this site. Tips on what to photograph for a good ID are here

While I'm putting very little time into it, a secondary iNaturalist project looking at the animals found interacting with Malacothamnus is here. Observations for this project are welcome as well.


Calflora is an alternative to iNaturalist for data collection on plants in California. I monitor these observations as well, but less regularly. Calflora is where I post most of my plant observations. If you want a reference population for a rare taxon, this is a good place to go as iNaturalist obscures locations of many rare plants that shouldn't be obscured. An example query for my observations of M. davidsonii is here. If you visit any of these locations, make an updated observation on Calflora or iNaturalist. This helps track how the populations are changing through time.

Calflora is the first place I to go for California plant information as it ties together data from many other sources including the Jepson eflora, CCH, Calphotos, CNPS, and iNaturalist. Like other sources of data on Malacothamnus, it is good to be cautious at present though. For example, many locations on the Calflora Malacothamnus maps use herbarium specimens and many of those specimens are currently misidentified. This will eventually be fixed when I resolve the taxonomy and can annotate these specimens.

Treatments and Identification

As mentioned above, there are several conflicting treatments. They are all problematic one way or another mostly due to lumping, splitting, and a lot of overlapping morphological characters. Treatments follow below. If you want help with identification beyond the treatments, see the iNaturalist Project section above. Calphotos is also useful to check IDs, but some photo IDs could be questionable.

I'm mostly following the Kearney treatment at present until I can resolve the taxonomic questions and produce something better. Kearney was more of a splitter, but this treatment still actually lumped several taxa from previous treatments. This treatment seems to follow the current evidence the most closely and includes rare taxa lumped by other treatments. The keys aren't perfect, but better than nothing. The Munz treatment mostly follows Kearney and is a bit simplified, so this is another good option. These treatments are missing both Malacothamnus lucianus and Malacothamnus enigmaticus. The Munz treatment is missing taxa from Mexico.

Do not use the Flora of North America or Jepson treatments. The 1993 Jepson Manual and Flora of North America treatments by David Bates are pretty much identical to each other. The taxa in these treatments were way over-lumped making them very problematic in relation to rare taxa. To the author's credit, he does say that the Kearney treatment is as justifiable as his. Likewise, the current Jepson Manual treatment is best avoided. Author Tracey Slotta made some good progress in splitting back out some lumped taxa based on morphological analyses, but her key is also problematic in various ways.

Draft regional keys and guides:
- Key to the Malacothamnus of Los Angeles, San Bernardino, and Kern Counties, CA
- Key to the Malacothamnus of Monterey and San Luis Obispo Counties, CA
- Key to the Malacothamnus of San Diego, Orange, and Riverside Counties, CA
- Key to the Malacothamnus of the San Francisco Bay Area, CA
- Key to the Malacothamnus of the Sierra Nevada Range, CA
- Illustrated guide and key to the Malacothamnus of San Diego, Orange, and Riverside Counties, CA
- Illustrated guide to distinguishing Malacothamnus from Sphaeralcea

- A morphological assessment of the Malacothamnus palmeri complex (Malvaceae)
- Malacothamnus enigmaticus (Malvaceae), a new rare species from the desert edge of the Peninsular Range in San Diego County, CA

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