Phacelia crenulata (Notch-leaved phacelia) ( )

There are two species of phacelia that are notable for their foul smell. Notch-leaved phacelia is an erect but little branched annual with thick and densely glandular stems. Its violet-purple flowers, with a touch of white at the petal base, highlight dark green leaves that are highly dissected into leaflets lobes with scalloped margins. The truly distinguishing feature of this plant is the unpleasant odor that has been described as a "skunk in syrup". It is widespread across creosote bush scrub up into pinyon-juniper woodlands and beyond across the western United States. "California Desert Plants, Philip W Rundel, Robert J Gustafson, Michael E Kauffmann."
Violet purple, on rare occasions white, these flowers form on one side of a curled branch in a manner suggestive of a scorpion's tail. Scorpionweeds are sticky annual plants with ill-scented, highly divided oblong leaves. They are bee-pollinated, but their pollen productivity in a flower population varies fiftyfold from year to year. Likewise, the duration of their flowering season may range from a week in a dry year to eight weeks in a wet one. Peak bloom time varies from late March to late April, when it is extremely common from grassland mesas down into low deserts. A relates species, Phacelia bombycina, replaces this one in southwestern Arizona. "Arizona Highways Presents Desert Wildflowers, 1988".