Denver EcoFlora Project's Journal

Gentian Drama

One of the last plants to bloom in the Denver metro area are the gentians. In fact, when you see gentians blooming you know that the first snowfall is about six weeks away! They are easily recognizable by their blue or bluish-purple, tubular flowers with longitudinal pleats or folds, and opposite, sessile leaves.

However, one gentian in particular, Gentiana affinis (pleated gentian), is taxonomically troubling. It is unclear whether or not we should recognize Gentiana bigelovii (Bigelow’s gentian) as separate from G. affinis. In iNaturalist, the two are lumped together under G. affinis. One of the best defining features in support of separation of the two species is flower color, with G. affinis having a bluish-purple corolla (flower color) and G. bigelovii having a pale blue corolla. Gentiana bigelovii is also typically found at lower elevations while G. affinisis found above 5,700 feet. This flower color is not preserved well in herbarium specimens, making it hard to use specimens to separate the two species.

Help Denver Botanic Gardens document the flower color of G. affinis along this elevation gradient by photographing as many plants as possible in the month of September. Post your findings to iNaturalist so they will be automatically added to the Denver EcoFlora Project. Let’s try to sort out this gentian drama together!

Gentiana affinis:

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?

1. Download the iNaturalist app or register online at iNaturalist.org
2. 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.
3. 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."
4. Post your findings on iNaturalist via the app
5. Your observations will automatically be added to the Denver EcoFlora Project
6. You can add an identification to your photo when you post your findings on iNaturalist, or leave it blank for others to identify.

HOW DO I PARTICIPATE GIVEN COVID-19?
As a participant, it is up to you how much or how little you take part. Please stay close to home and maintain a social distance of 6 ft. from people. Wear a cloth mask in public areas. Respect closures and avoid places of high use. Do only what feels safe for you and your family and is in accordance with your local regulations.

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.

A common shrub in the metro area and surrounding foothills is rubber rabbitbrush, Ericameria nauseosa (formerly Chrysothamnus nauseosus). It is even 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. Rabbitbrush is a member of the Asteraceae (sunflower) family, and as such has flowers arranged in heads. The rabbitbrush heads are specifically comprised of only yellow “disk” flowers.

Rubber rabbitbrush synthesizes a variety of compounds (terpenoids) that make it distasteful to most herbivores. However, rabbitbrush beetles (Trirhabda nitidicollis) have adapted to tolerate these noxious compounds. You may remember seeing large masses of blue-green larvae on rabbitbrushes in the spring. These have now metamorphosed into yellow- and black-striped adults, where they continue to feed on a diet of rabbitbrush leaves. These compounds also make these beetles toxic to most predators.

Help Denver Botanic Gardens document the range of rabbitbrush and the rabbitbrush beetle by photographing as many plants and beetles as possible in the month of October. Post your findings to iNaturalist so they will be automatically added to the Denver EcoFlora Project.

Ericameria nauseosa:

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?

1. Download the iNaturalist app or register online at iNaturalist.org
2. 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.
3. 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."
4. Post your findings on iNaturalist via the app
5. Your observations will automatically be added to the Denver EcoFlora Project
6. You can add an identification to your photo when you post your findings on iNaturalist, or leave it blank for others to identify.

HOW DO I PARTICIPATE GIVEN COVID-19?
As a participant, it is up to you how much or how little you take part. Please stay close to home and maintain a social distance of 6 ft. from people. Wear a cloth mask in public areas. Respect closures and avoid places of high use. Do only what feels safe for you and your family and is in accordance with your local regulations.

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.