Observation of the Month: Erodium (Geraniaceae)
White-stem Filaree/Storksbill (E. moschatum) and Red-stem Filaree/Storksbill (E. cicutarium) https://www.inaturalist.org/observations/19165993 by tchester
With lots of rain so far this season, it's a good year for annuals and that means an abundance of filaree. The names filaree and storksbill are applied to multiple plants in the family Geraniaceae (8 in San Diego County). Some are native to San Diego, but most are non-natives. Two of the non-native species in the genus Erodium have compound leaves which helps to separate them from other members of this genus and from a similar-looking species now assigned to the genus California, all of which have simple leaves. While both Erodium moschatum and E. cicutarium are widespread in San Diego County, E. moschatum is rare in the desert and is not found at our highest elevations (above about 5,000 feet) unlike E. cicutarium.
Don't let the common names of white-stem and red-stem filaree (or storksbill if you prefer) fool you into thinking that all you have to do is look for the color of the stem to tell these two apart. While red-stem filaree may have a reddish tinge to the stem, it often does not. Instead, focus on the leaflets: the leaflets of E. cicutarium are more finely dissected than the leaflets of E. moschatum. In addition, the tips of the sepals of E. cicutarium are bristly while the tips of the sepals of E. moschatum are not. Each of these characteristics of the leaflets and sepals can be seen in the observation of the month by @tchester which conveniently shows both species side by side in the photos.
