This flower looks similar to Baccharis salicifolia (Mulefat)...however its leaves look quite different.. So, what is it?

The Mulefat is a browse source for deer and elk. It is considered an important butterfly plant. The name "Mulefat" comes from the days of the gold rush when miners would tie their mules to the bush and allow them to browse throughout the day.
The Cahuillas tribe had many uses for the plant such as eyewash, baldness preventative, and building materials.
https://www.sdnhm.org/archive/fieldguide/plants/bacc-sal.html

Here is a link that might be useful: Baccharis salicifolia