October EcoQuest - Rabbitbrush Roundup
Rabbitbrush are one of our most conspicuous fall flowering plants in the Denver metro area, but identifying among the different species can be a challenge. There are two species of rabbitbrush, often confused with one another – Ericameria nauseosa (rubber rabbitbrush) and Chrysothamnus viscidiflorus (yellow rabbitbrush). Although rubber rabbitbrush and yellow rabbitbrush are both considered rabbitbrushes, they are now placed in two separate genera. Much of the confusion between the two comes from this previous assignment – the older name for Ericameria nauseosa was Chrysothamnus nauseosus. Additionally, both rabbitbrush species are sometimes confused with snakeweed, Gutierrezia sarothrae.
Rabbitbrush and snakeweed are all members of the Asteraceae (sunflower) family, and as such have flowers arranged in heads. Telling the three apart though is actually quite easy! Ericameria nauseosa is usually a large shrub, with straight leaves and heads comprised only of yellow “disk” flowers. Chrysothamnus viscidiflorus is far less common than rubber rabbitbrush, and is easily distinguished from the other two species by its twisted leaves. And lastly, Gutierrezia sarothrae is a smaller shrubby plant, separated from both rabbitbrush species by the presence of yellow “ray” flowers in addition to the yellow disk flowers in its heads (versus only disk flowers).
Rubber rabbitbrush is often used as a landscaping plant because of its drought tolerance and prolific floral displays. Its common name refers to the plant being a source a rubber (although extraction is too expensive to be competitive), and its scientific name references the sickening consequences of consuming the leaves. Rubber rabbitbrush synthesizes a variety of compounds (terpenoids) that make it distasteful to most herbivores.
Help Denver Botanic Gardens document the range of Ericameria nauseosa, Chrysothamnus viscidiflorus, and Gutierrezia sarothrae by photographing these plants in the month of October. Post your findings to iNaturalist so they will be automatically added to the Denver EcoFlora Project.
WHAT IS AN ECOQUEST?
EcoQuests, part of the Denver EcoFlora project, challenge citizens to become citizen scientists and observe, study, and conserve the native plants of the City via iNaturalist, an easy-to-use mobile app.
HOW DO I GET STARTED?
Download the iNaturalist app or register online at iNaturalist.org
Take photos of the plants in bloom that you find on your daily neighborhood walk. It is ok if they are weeds! But avoid taking photos of cultivated plants in gardens or in your home.
If you are concerned about revealing the location of sensitive organisms or observations at your own house, you can hide the exact location from the public by changing the "geoprivacy" of the observation to "obscured."
Post your findings on iNaturalist via the app
Your observations will automatically be added to the Denver EcoFlora Project
You can add an identification to your photo when you post your findings on iNaturalist, or leave it blank for others to identify.
WHAT IS THE GOAL?
The EcoFlora project is designed to meaningfully connect citizens with biodiversity, and to assemble novel observations and data on the metro area’s flora to better inform policy decisions and conservation strategies.
