Evan Jackson

Echinacea Project 2018

Biology, College of Wooster 2020

Research Interests

Ever since I was a kid I’ve always had an interest in forensics. It wasn’t until my second year in college that I started developing a passion for studying ecology. I decided to take a gateway to ecology, evolution, and organismal course as well as an agricultural entomology course and have enjoyed the subject matter. I’m not fully committed to the subject yet, but I am looking forward to working in the field this summer!


I’m from Chicago, Illinois and I am currently working in the Chicago Botanic Garden’s lab. I’m currently working in the Plant Science Center where I’m cleaning Echinacea heads, identifying pollen, and becoming familiar with the types of bees that visit Echinaceas. When I’m not working in the lab, I’m at home spending time with my family or making music.

Rematriation 2018

During the summer of 2017, Lea and I carried out a project we called “Rich Hood” (richness of floral neighborhoods). This involved setting up 2 x 2 m square plots around Echinacea plants in the remnants, and getting cover class estimations for all species present. We also harvested flowering Echinacea heads, and there is more specific information in the flog post about reproductive fitness in the remnants. Nina Denne, a student at Carleton, completed an externship project comparing the floral neighborhood with the seed set of the collected Echinacea heads.

On May 6th and May 7th, 2018, I returned achenes to the remnants that were not sampled for the x-ray. I returned achenes to all the remnants that were in our study except for Landfill and SPP, which will hopefully be rematriated later this spring. At each site, I staked to points where heads had been collected (using stake file stakeReturnRichHood.csv), found the matching tags within the plot, and spread achenes in about a 20 cm radius around last year’s stalk. In some cases, if I couldn’t find the tag within a reasonable time of searching, I spread the achenes around the point I staked to.

It was nice to see what the remnants looked like in the spring, but I didn’t see any tiny Echinacea rosettes yet. Some of last year’s heads out there had dispersed all of their achenes, but many were still holding on to a few.

An Echinacea head with a few achenes left to disperse.


The competition concludes

Greetings floggers!

The interspecific competition has offered the following results:

  • Interspecific competition of growth rate is greater for Bromus kalmii with Elymus canadensis compared to intraspecific competition of Bromus kalmii at this stage of growth.
  • The growth rate of interspecific competition for Elymus canadensis with Bromus kalmii demonstrated a negligible change compared to intraspecific competition.

*To view the full write up click here: Interspecific comp.

Fig 1: Vertical black line on each histogram indicates the mean value for each treatment (E. canadensis vs B. kalmii, E. canadensis vs E. canadensis, B. kalmii vs E. canadensis, or B. kalmii vs B. kalmii) of interspecific competition and intraspecific competition. (F) indicates the focal plant.

Likewise, my spring semester internship has concluded as well. This experience has been an amazing and immersive learning opportunity. Within the past week, since the end of my internship,  I’ve noticed a shift in the way I think. I’ve started observing plants, not just for their beauty, but also for their seed composition and amazing structures. I have found  an appreciation and curiosity for the conservation of our native species and the ecosystems they take part in.

The CBG is a wonderful place that cultivates the excitement of science. Whatever the future holds, I will maintain the same attitude as I have during this experience. From day one, I knew I was in a special place and needed to absorb every moment of it. This internship has truly exceeded my expectations.

In closing, I’d like to thank Stuart and Tracie for their guidance, support, and exposure to a fascinating study of plant science. I also would like to thank them for transplanting my grasses to the prairies of Minnesota, where they can grow to their full potential 🙂

E. canadensis transplanted to the MN prairie by Tracie Hayes and Stuart Wagenius. Grown from seed by Danielle Oilschlager 🙂



Perfecting the X-ray image: EBImage package in R

Hi all! Stuart and I are in the process of figuring out the best way to edit our x-ray images of Echinacea achenes so that it is easy to classify them:

  • Are all achenes (full and empty) visible?
  • Is it easy to tell between full and empty achenes?
  • Can achenes within clumps be identified individually?

Example x-ray image with achenes, before edited

Here is an example of an x-ray image that is tricky to classify. All of these achenes are empty, so they are more translucent and harder to see. Also, many of these achenes are in clumps, so getting the correct count of empty achenes is a challenge.

Example x-ray image before edits, with circled clump

A single clump has been circled in green in this image. This clump has 3 empty achenes, but we want that to be more obvious. To edit our images, we have been working with the EBImage package in R. Here are a few examples.

Edited example #1

This edit is helpful because it makes the background darker so that it’s easier to pick out achenes. The 3 in the clump are still kind of hard to pick out, though. Here is the code we used:


x <- readImage('')

kern = 2000*makeBrush(99, shape = 'Gaussian', sigma = 5)
display(whiteTopHat(x, kern))

This example is blurred a bit, which is helpful for seeing achenes in their entirety. This is the code we used:


x <- readImage('')

display(gblur(x, sigma=0.8))

There are endless possibilities if using multiple EBImage functions on one image, and we are looking for some guidance. If you have experience with EBImage, what do you think are the best combinations of functions for reaching our goals? Thanks for the help!


Resources for germinating seeds

Do you want to germinate some seeds? A while ago Andrea Kramer recommended four resources to find out about seed germination. I’m copying them here:

1. A good place to start with when you are working with a new species: This database goes along with the 2014 Baskin seed book, below. It is free but requires sharing your contact info.

2. The book: Baskin, C. and J. Baskin. 2014. Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination. 2nd ed. Academic Press, New York.

3. The Royal Botanic Garden Kew has a Seed Information Database:

4. A handy paper with guidelines for a “move-along” experiment: Baskin, C. C., and J. M. Baskin. 2003. When Breaking Seed Dormancy Is a Problem: Try a Move-along Experiment. Native Plants Journal 4:17-21.


5. Prairie Moon Nursery has a Cultural Guide that lists germination requirements for hundreds of Midwestern U.S. species. It’s a big excel spreadsheet that you can access from this page….

6. For germinating Echinacea angustifolia, we use a modified version of the protocol developed by Feghahati & Reese in 1994. We don’t use fungicide, but otherwise stick pretty close to their recommendations.

The competition continues..

Over the past few weeks, Elymus canadensis and Bromus Kalmii have taken to the plots for a battle of resources. When I initially began this experiment, I hypothesized that Panicum virgatum would take the lead, since it develops a ribosomal root system and is known to be an aggressive prairie species. However, out of 500 seeds, only 1 P. virgatum has germinated and sprouted. For that reason, I’ve decided to eliminate P. virgatum from the data analysis. Although, I have planted the lonely P. virgatum so that it can later be transplanted to the prairies of Minnesota. I later suspected that E. canadensis would take the lead in sprouting. However, B. kalmii has currently overthrown the number of germination/sprouting. There are still a few weeks to go with this experiment before analyzing the data collected on height. With that said, it could go either way. The grasses are growing taller and faster than any of us expected. I take measurements weekly and can already conclude that competition is occurring. The leading height in each treatment varies, indicating that one of the species is achieving more resources than the other. More updates and photos to come!



Competing species – 2 seedlings to a cell

Bomus Kalmii germinating/sprouting in the agar-petri dish

The one and only germinating/sprouting Panicum virgatum



Hi everyone! Tracie, Kris (another PBC grad student), and I had a great time presenting this year at the Midwest Ecology and Evolution Conference in Kalamazoo, MI. Here’s a look at my poster that I presented about pollen on Echinacea as a part of the ongoing Floral Neighborhood Communities project:

Do pollen loads differ among native bee visitors to Echinacea angustifolia?

A picture of me presenting!

MEEC 2018 was awesome! For any undergrad or graduate student interested in attending an inexpensive, regional conference I would highly recommend it. It was great to network with fellow graduate students and hear all about the great research ongoing here in the region!

MEEC 2018 – Tracie

Hi flog! This past weekend I presented my cluster/spatial scale research at the Midwest Ecology and Evolution Conference at the Kellogg Biological Station. Check out my poster!

Synchrony of flowering phenology within clusters depends on the spatial scale at which clusters are defined – Tracie’s MEEC 2018 poster

Tracie with her poster at MEEC 2018


Status update on the interspecific competition experiment!

The seeds were pulled out of their pre-treatment and were moved into the growth chamber for germination to take place. After 5 days, a handful of E.canadensis were germinating, along with B. kalmii at a close behind rate. P. virgatum has yet to germinate, though at this time it’s still early. After filling three 20×10 flats with soilless soil, prior to removing the seeds from cold stratification, the cells (tiny plots on flat) where numbered in preparation of seed transport. By choosing soilless soil I can ensure a uniform system of adequate water retention and proper drainage. As a method for watering, my mentor Stuart has suggested to bottom-water the plants to avoid dampening one area of soil more than another area, which can occur when watering from above. By using sterilized tweezers, I carefully selected a germinating seed from a randomly ordered petri dish. Once the radical was successfully extracted from the agar, the seed was planted into its designated cell. Before transportation took place, I created a few randomizing sheets on an application called R. The sheets randomized the petri dish order, as well as the treatment (species vs. species) placement. The reason we want the order of everything to be randomized is to avoid any biased decisions. This also helps to yield accurate results. I was able to plant over 100 treatments this past week for E. canadensis and B. kalmii. I’m hoping this week P. virgatum will begin germinating.

With that said, the next phase has begun- measurements of growth. To reiterate the purpose of this experiment, I will observe the growth of each species in relation to the species it’s competing with for resources such as water, root space, and light. I will do this by measuring their height on a weekly basis. I want to determine which species will be the most dominant in this early stage of development. On Friday, I started measuring my little sprouts. The tallest I have observed so far has grown to 70 mm. 🙂

This process is very exciting, as I’ve mentioned before. To be able to plan something out so specifically detailed and to watch the process actually happen is nothing short of magical 🙂 It’s really fascinating to watch these little seeds germinate into such beautiful green sprouts!

Elymus canadensis germinating

Bromus kalmii germinating

Carefully transporting germinated seeds into their randomly assigned cell

sprouting and reaching for light 🙂



Recap of past year & summer 2017 field season

It’s time to prepare annual reports to NSF for our two long-term awards through CBG & through UMN. The period covers 1 April 2017 through 31 March 2018. So, here’s a brief recap of activities from the past 12 months including the summer 2017 field season.

Last spring we were busy in the lab. Led by interns Amy & Scott, volunteer citizen scientists at the Chicago Botanic Garden started cleaning heads harvested in summer 2016 to count all of the achenes to generate a detailed and precise dataset of annual plant reproductive fitness. We were way behind because of the huge flowering year in 2015. We worked all fall & winter and we are in good shape now. Led by Tracie, we are cleaning 1148 heads harvested from plots in 2017, which we will finish over this summer.

Several undergraduate students have worked on projects in the lab, including Nicolette, Ashley, Marisol, Nina, Trevor, and now Danielle. They are all gaining experience, learning a lot, and contributing to science! Graduate students are hard at work too. Lea has analyzed all of her summer phenology data on Solidago & Liatris. Kristen is working on the bee collection from last summer with Mike. They are both making research plans for summer 2018.

Last December, we submitted a paper to Oikos titled “Pollinator-Mediated Mechanisms for Increased Reproductive Success in Early Flowering Plants.” We haven’t heard anything for 101 days & wonder if it has disappeared into a black hole.

Our team accomplished a lot in summer 2017! The 2017 summer team, shown below, included three undergraduate students (Ashley, Will & Wes), a high-school student (Anna), two graduate students (Lea & Kristen), and two recent college grads (Tracie & Alex)–not to mention the usual suspects, Gretel, Ruth & Stuart. We summarized progress on many summer projects last fall & made flog posts. Here are links to the updates organized into six groups.

First, we measured survival, growth, and flowering effort of our model plant, Echinacea angustifolia, in several experimental plots. The earliest was established in 1996 and the most recent in 2015:

Second, we measure other traits in these plots, including flowering phenology. We also have some treatments, such as pollen addition and aphid addition, which we apply every year. Will has super-cool estimates of the heritability of flowering timing. He is polishing the manuscript and will submit it soon. Amy W. has a manuscript in review that quantifies reproductive synchrony in the 1996 cohort of plants. She estimated how much within-year synchrony (daily phenology) and among-year synchrony (annual flowering) contribute to long-term mating opportunities.

Third, we make observations of Echinacea plants in natural prairie remnants in our study area, including flowering phenology, survival, reproduction, and incidence of disease. Scott is investigating effects of fire on population growth rates in our remnants using a life-table response experiment approach. While she is on sabbatical, Amy D. is analyzing the seedling establishment dataset.

Fourth, we study plant species other than Echinacea angustifolia and we are very interested in pollinators, including native solitary bees.

Fifth, two REU participants worked on our Team last summer. Here are updates of their projects.

Sixth, we are worried about non-native Echinacea plants that are used in restorations and how they impact populations of the native Echinacea angustifolia. We have several ongoing experiments that investigate a population of Echinacea pallida introduced within our study area.

The Team from summer 2017