Bushmallow Challenge 5 - The Northernmost Bushmallows

The northernmost bushmallows are all sometimes treated under Fremont's bushmallow (Malacothamnus fremontii) which includes Malacothamnus helleri, Malacothamnus howellii, and a new species I'm describing. Towards the northern end of the range, known locations become sparse. Below is a map which shows historic collections as orange circles and locations I've found as white circles with Xs in them.

It would be very useful to find more locations in these northern regions. Are these really as rare up there as suggested? Are the various forms distinct or do they grade into each other in the intermediate areas? Do they go even farther north? While they go up close to Redding on the west side of the Central Valley, they aren't known north of Amador County on the east side. Is there a reason for this? Can anyone find some northern populations on the east side?

If you are in the area, keep an eye out or specifically go searching for them. Here's a photo of the northernmost form I've found so far.

Relatively recent burn areas are the best place to look for Malacothamnus. The second year after a burn is probably the best time to look as the plants should be fairly large and not yet outcompeted by returning chaparral. As soon as five-years after a burn, many or all plants may be dead, but some may live much longer. Those persisting longer are often on the edges of openings and in moister areas. Malacothamnus are most often found in burned chaparral but are occasionally found in burned woodlands as well. Follow this link for an interactive burn map to find likely areas to search for plants.

See also my post here on what to focus on if you want to be able to ID a bush-mallow from photos.

Update June 2021:
The northernmost known Malacothamnus population was recently discovered by iNat users. See here. This is a new species I'm describing, which is currently only known from this observation and the Ono to Platina area of Shasta County. This observation suggests it may be found in other locations within the same burn and possibly even further north or east. Likewise, it suggests additional populations between the known ones may be found.

Posted on June 22, 2018 01:42 AM by keirmorse