Lesser Celandine Seekers
A Springtime Survey Effort with PA iMapInvasives
This StoryMap was presented as a part of a webinar training for the Lesser Celandine Seekers Survey Event. Learn how to participate in the Lesser Celandine Seekers by reading this StoryMap or by watching the recorded webinar:
Where is Lesser Celandine Found in Pennsylvania?
At a broad, state-wide scale, lesser celandine can be found all over Pennsylvania. The most obvious concentrations of lesser celandine populations occur near Philadelphia, Pittsburgh, and other cities and towns. Reports of lesser celandine are much more scattered and sparse in the rural areas of the Commonwealth.
When we start to look closer, however, we see that lesser celandine infestations tend to stay contained within watershed boundaries. This means that, at local scales, there are many smaller watersheds where lesser celandine is only present at a few places or is completely absent altogether. In local watersheds where lesser celandine is only emerging or absent, we are presented with opportunities for early detection and rapid response.
Explore the map below to discover where lesser celandine occurs around Pennsylvania and your own community. See which watersheds have lesser celandine infestations at both broad (HUC06-HUC08) and local (HUC10-HUC12) scales ( More about HUC watersheds ). Point data is aggregated from iMapInvasives and iNaturalist (records up to 100 meters of mapping accuracy). Click on individual points for additional record details.
Lesser Celandine Seekers (2025) - Pre-Event Point Map
Monitoring Beyond Presence/Absence
Although rural parts of Pennsylvania may have few or zero lesser celandine populations, this plant has been established in the urbanized areas around Philadelphia and Pittsburgh for many decades. Although new, early-detection populations are unlikely to be found around these and other cities, that should not discourage potential Lesser Celandine Seekers from joining in on the survey efforts this spring.
In established and well-known lesser celandine populations, new data can allow natural resource professionals to monitor changes in these populations over time. This might include increases or decreases in the total infested area and information about the novel ways that lesser celandine may be interacting with the environment.
The importance of monitoring data is stressed to let potential participants know they do not need to travel to remote parts of the state and discover early detection populations to contribute valuable data to the Lesser Celandine Seekers event. However, these types data are also beneficial to collect in early detection scenarios, as they establish a baseline of information for new populations.
A long-established lesser celandine population that has become dominant in a floodplain. Even though this population is well-documented, valuable data can still be collected here.
Types of monitoring data that you can collect for lesser celandine populations (in both established and early detection populations):
Phenology Data
Phenology is defined as the timing of vegetative and reproductive events in plants and their relationships with abiotic and biotic factors, e.g., flowering times in relationship with seasonal rainfall. Studying phenology of plants is critical to our understanding of how species are adapting to a changing environment. When making records for lesser celandine during this event, consider asking and answering the following questions:
- What growth stage are the leaves in? Are they developing and unfurling? Are they fully opening? Are they yellowing and senescing, signaling the end of the growing period?
- What growth stage are the flowers in? Are they still light green buds at the tip of a stem? Are the petals developed and yellow, but not fully open? Are the flowers in full bloom? Are the petals dropping? Are fruits forming where the flower once was?
- Are tubers present in the leaf axils? If so, how big are they? Do they fall off of the stem easily?
Lesser celandine senescing; the leaves are beginning to wither and relocate their nutrients to the tubers, signaling the end of the growing season for lesser celandine.
Ecology Data
Collecting additional notes on how lesser celandine might be interacting with other organisms, as well as their habitat overall, can help us fully understand the impacts that lesser celandine has on ecosystems. When making records for lesser celandine during this event, consider asking and answering the following questions:
- Are the other plants growing within or around this lesser celandine population? How many different types? Can you identify some or all of the other plants growing with lesser celandine? Are they native, non-native, or a mix of both?
- Are insects or other invertebrates present around this lesser celandine population? If so, what kinds of insects are they (bees, flies, moths, butterflies, beetles, ants, etc.)? Are they interacting with lesser celandine flowers?
- What type of habitat is this lesser celandine population growing in? Is it growing near characteristic features like a stream or creek? Is the soil inundated with water? Is the soil muddy, sandy, or something else?
Lesser celandine growing with a mix of other plant species.
Recording Additional Monitoring Data
The iMapInvasives Web Map offers additional data fields to add information on phenology and habitat to a record.
When creating a record with the iMapInvasives Classic Mobile App, these options are not visible in-app. However, there is a text box for observation comments where any monitoring data that you might collect can be entered.
An example of lesser celandine monitoring data collected in the iMapInvasives Classic Mobile App.
Note: Phenology and ecology monitoring data are completely optional and are not required to participate in the Lesser Celandine Seekers event.
How Can I Participate in the Lesser Celandine Seekers?
1. Request an Account
To report data to iMapInvasives, request a free account at PAiMapInvasives.org (If you already have an account, skip this step). You will need an account to report via the iMapInvasives mobile app or online database. Follow the screenshots below to learn how to create an iMapInvasives account.
Click on Login/Register at paimapinvasives.org .
Complete the Sign Up form to request a free account.
2. Join the Project
Once you receive an iMapInvasives account, login to the iMapInvasives online database and request to join the "Lesser Celandine Seekers (2025)" project. Follow the screenshots below to learn how to join the project.
After requesting to join the "Lesser Celandine Seekers (2025)" project, an iMapInvasives administrator will approve your request. Once approved, you will be notified via email.
All participants' survey data must be tagged to the "Lesser Celandine Seekers (2025)" project to qualify as part of the event.
*If you have an existing iMapInvasives account, and you registered for the webinar training on February 27th, you may have already been added to the "Lesser Celandine Seekers (2025)" project by an administrator. Check the "Projects" section of your account profile to find out.
How to Join the "Lesser Celandine Seekers (2025)" Project
After logging into iMapInvasives online , select "Projects" from pop-up menu in the upper-left corner.
Use the search box to find the "Lesser Celandine Seekers (2025)" project.
Click "Request to Join Project" from the "Lesser Celandine Seekers (2025)" project page. Afterwards, await an email from an iMapInvasives administrator letting you know your request is approved.
How to Check if You're Already Added to the Project:
Select "Your Account" from the pop-up menu in the upper-left corner of the iMapInvasives online database.
Check the Projects section of your account profile to see if you have already been added to the "Lesser Celandine Seekers (2025) project. If yes, you can begin your surveys. If not, request to join the project.
3. Report Your Findings
Learn how to report lesser celandine presence and absence findings to iMapInvasives by watching the following video tutorials below.
Note: These videos are NOT specific to the Lesser Celandine Seekers event; they show step-by-step instructions on how to report an invasive species to the iMapInvasives database.
Not-Detected Reports: Users can choose to include a photo of the area searched when submitting a Not-detected report to iMapInvasives.
Using the iMapInvasives Classic Mobile App
How to Use the iMapInvasives Mobile App
Ensure Your Data is Tagged to the "Lesser Celandine Seekers (2025)" Project When Using the Mobile App
In order for your data to be included in the Lesser Celandine Seekers event, your presence and absence records must be tagged to the "Lesser Celandine Seekers (2025)" project. Refer to the screenshots below if you are unsure of how to tag your records to a project in the iMapInvasives Classic Mobile App.
Upon opening the iMapInvasives Classic Mobile App, select the option to refresh your iMap Data, if prompted.
When creating an observation in the Classic Mobile App, click on the drop-down menu under "iMap 3 Project: (optional)".
From pop-up Projects List, select "Lesser Celandine Seekers (2025)"
After selecting "Lesser Celandine Seekers (2025)" from the menu, your observation will now be tagged to the Project.
Photo Limit with Classic Mobile App
If using the Classic Mobile App to report data to iMapInvasives, only one photo can be added per record. However, additional photos can be added by searching for and editing your record(s) in the online database.
Creating Records in the iMapInvasives Online Map
How to Create a Presence Record in iMapInvasives
How to Create a Not-Detected Record in iMapInvasives
Photography Matters! Taking Identifiable Pictures of Lesser Celandine
All data that comes into iMapInvasives is reviewed by experts to ensure correct species IDs. The photographs that iMapInvasives users and event participants attach to their records are the primary way that we verify species identity when confirming records. As such, please consider the following tips when reporting lesser celandine during the Lesser Celandine Seekers event:
#1: Capture Distinguishing Characteristics
Take up-close images that show distinguishing characteristics of the species you are recording. For lesser celandine, this could be features like the flowers, sepals, and leaves.
Having photos that can be used to easily verify the species identity take priority over photos that show the extent of an invasive species infestation. Infestation extent can always be described in the general comments for a record; distinguishing characteristics are more difficult to describe with words alone!
If possible, try taking photos low to the ground and at an angle to capture both distinguishing features and invasion extent.
Lesser celandine, photographed low to the ground at an angle that shows both identifying characteristics and the extent of invasion.
#2: Clarity and Focus
Be sure your photos are crisp, clear, and in-focus. Blurry and out-of-focus images are difficult to use when confirming species IDs! Additionally, make sure that lesser celandine is the main subject of your photo! If lesser celandine is not the focal point of an image, then its presence in the photo can be difficult to confirm.
Photo where lesser celandine is present, but it is not the focal point of the image.
#3: Size and Scale
Include items in the image to show the size and scale of the species you are recording, such as a hand, coin, or ruler. Items that might contain personal information, such as drivers licenses and credit cards, are NOT appropriate to include for scale.
Lesser celandine leaf photographed with a ruler to provide a sense of size.
View Your Findings!
You can view records in iMapInvasives submitted by yourself or other lesser celandine seekers by using the "Filter Records" tool in the online database. You can also view just your findings, separate from other users. Follow the screenshots below to learn how to view data from the Lesser Celandine Seekers event.
Login to iMapInvasives, and from the main map page, locate the button called "Filter Records" at the top of the screen.
On the General tab of the tool, search for "Lesser Celandine Seekers (2025)" in the Project section. Then click Apply Filter.
Turn on the Confirmed, Unconfirmed, and Not-Detected data layers. After data loads, zoom the map to get a closer look at the data that appears.
Navigate to the "Filter Records" tool. On the General tab, activate the toggle next to the section titled "Filter on Your Records". You can further refine your search by including "Lesser Celandine Seekers (2025)" in the Project section. Click Apply Filter.
Additional Resources
Learn more about lesser celandine from the following online resources:
- Invasive Plants in Pennsylvania: Lesser Celandine - Pennsylvania Department of Conservation and Natural Resources
- Invasive Species Spotlight -- Lesser Celandine - Pennsylvania Department of Conservation and Natural Resources
- Don't be Deceived by This Beguiling Springtime Plant - PennState Extension
- Lesser Celandine: An Aggressive Non-Native Spring Ephemeral - Ohio State University
- Lesser Celandine - New York Invasive Species Information
Invasive Species Spotlight -- Lesser Celandine
Contact Information
Brian Daggs
Do you have questions about the 2025 Lesser Celandine Seekers event or about lesser celandine in general? Contact Brian Daggs at the Western Pennsylvania Conservancy and the Pennsylvania Natural Heritage Program.
- Email: bdaggs@paconserve.org (preferred)
- Phone: 412.586.2419
