Questions for Anita Cholewa

Learn more about my research In December 2008, Anita Cholewa answered visitors questions about forensic botany.

Your Comments, Thoughts, Questions, Ideas

Joe's picture
Joe says:

How did you get started as a forensic botanist?

posted on Tue, 12/23/2008 - 5:07pm
Anita Cholewa's picture

It was really by accident. An investigator needed someone who could help identify evidence that consisted of bits and pieces of plants.

posted on Mon, 12/29/2008 - 11:57am
Anonymous's picture
Anonymous says:

Can you give a memorable example of a time when you were called in to help solve a crime? Your work is facinating!

posted on Mon, 12/29/2008 - 10:23am
Anita Cholewa's picture

Most of my cases have been memorable - any time I can help to solve a crime is rewarding.

One example is a murder case in which the plant materials helped tie a suspect to the weapons. The plant particles on his clothes indicated he was in the vicinity where the weapons were tossed.

Another example is a child molestation case in which plant matter on the inside of the suspect's clothes indicated he was lying. He claimed he was only holding the child when the child barfed on him. But the seeds and plant juice wouldn't have gotten inside his jeans if that were the case.

posted on Mon, 12/29/2008 - 12:04pm
Anonymous's picture
Anonymous says:

You admit to being a self-professed expert in plant trivia. What is your favoriate bit pf plant trivia?

posted on Mon, 12/29/2008 - 10:25am
Anita Cholewa's picture

Boy that's a tough question - there are so many plants and so many interesting little tidbits about them - I can't really say what my favorite trivia piece is.

But here's a couple of examples ...
1. Minnesota has 15 different species of carnivorous plants!
2. Cherries have little glands on the leaves that encourage ants to visit and then the ant can prey on other insects that would be damaging to the cherries.

posted on Mon, 12/29/2008 - 11:44am
Anonymous's picture
Anonymous says:

What are the carniverous plants that live in MN?

posted on Thu, 01/15/2009 - 1:47pm
Anita Cholewa's picture

Most of our carniverous plants occur in the bogs (that's a typical habitat) usually found in the northern part of the state but some occur in lakes.

We have the northern pitcher plant (downward pointing hairs on the pitcher-shaped leaves cause insects to lose their grip and fall into the enzyme-laced water in the bottom), the common butterwort (which has sticky leaves like flypaper) and occurs on the wet rocks along the North Shore, five different species of sundews (which have sticky hairs on the leaf surface that trap insects and then the leaf curls up and over the insect), and eight different species of bladderworts which live in lakes (these have tiny trap-door appendages on their submerged leaves; when microscopic water creatures venture close enough, the trap-door opens and the in-rushing water carries the creature into the trap).

posted on Sun, 01/18/2009 - 1:39pm
Anonymous's picture
Anonymous says:

How can plants help determine the time a crime was committed?

posted on Mon, 12/29/2008 - 10:25am
Anita Cholewa's picture

The answer depends on the type of crime.

In cases involving poisoning, the amount of digested vegetable matter can be analyzed. Different vegetables are digested in the stomach at different rates, so the examination of stomach contents can then be used to tell when the poisoning occurred.

In cases where something (say a bag of loot) is tossed into the weeds along a roadside, the amount of green color in the plants that were covered by the bag can give an approximation as to when the bag was tossed. Chlorophyll in plants give them their green color but this is dependent on sunlight. When covered by something (the bag of loot) the plants will lose color because the chlorophyll stops working. This loss of color, however, can take two to several days, so this is only an approximation of timing.

posted on Mon, 12/29/2008 - 11:56am
Anonymous's picture
Anonymous says:

who first thought of using plants to investigate?

posted on Mon, 12/29/2008 - 3:37pm
Anita Cholewa's picture

The first official record in the US that I've found, of plants helping solve crimes was with the kidnapping of the Lindbergh baby in 1932.
The wooden ladder that was propped against the Lindbergh house was analyzed for the type of lumber used. A peculiar mark made in the wood was traced back to a particular lumber mill. Then all their records were examined to see who had bought the wood and that led the investigators to Bruno Hauptmann who was a carpenter and worked for the Lindberghs.

posted on Fri, 01/02/2009 - 4:39pm
From the Museum Floor's picture

Why are flowers never green?

posted on Wed, 12/31/2008 - 6:45pm
Anita Cholewa's picture

The green color in plants comes from the chlorophyll molecules, which have an important role in photosynthesis.

Flowers don't play a role in photosynthesis and thus don't produce the chlorophyll molecule (no sense wasting energy making something you don't need). Instead the flowers serve to attract pollinators.

Different pollinators are attracted to different colors, so the flowers that depend on animal pollinators (insects and birds usually) are colored to attract those pollinators. For example, bees are attracted to blues and violets and tend to visit blue or violet flowers; our hummingbird is attracted to red flowers; and so forth.

posted on Fri, 01/02/2009 - 4:50pm
From the Museum Floor's picture

How did Spiderwort flowers get their name?

posted on Wed, 12/31/2008 - 6:46pm
Anita Cholewa's picture

I'm not sure about this one.

The word wort is an Old English name for plant, specifically a plant used in herbal medicine. Perhaps this plant was used to alleviate inflammation caused by a spider bite.

posted on Fri, 01/02/2009 - 4:55pm
Anonymous's picture
Anonymous says:

What is your favorite part of your job?

posted on Tue, 01/06/2009 - 3:10pm
Anita Cholewa's picture

I have always liked solving puzzles. Trying to identify a plant based on just a portion of that plant is like a puzzle with some of the pieces missing. It's fun to be able to look at a plant and say oh that is such-and-such; it's even more fun when the answer comes in the middle of the night - oh I know where I've seen that plant before or I know what that plant was! Additionally, since I am also a museum curator and have access to a very large collection of dried plant specimens, I can look through those museum specimens and find one that matches my plant. "Ah ha! I was right!" Puzzle solved!

posted on Wed, 01/07/2009 - 7:58pm
Anonymous's picture
Anonymous says:

Are there lots of forensic botanists or is it a small group? I suspect it is a small group, but are you organized in any way?

posted on Wed, 01/14/2009 - 4:17pm
Anita Cholewa's picture

Forensic botanists form a small group indeed - most of the ones I know work at universities but there are some that work at the FBI's Quantico lab.

posted on Sun, 01/18/2009 - 1:41pm
Anonymous's picture
Anonymous says:

How many times a year are you called in to help with a case on average? Does it matter the time of year?

posted on Wed, 01/14/2009 - 4:17pm
Anita Cholewa's picture

I rarely get more than one or two cases a year and so far never in winter.

Almost all the cases I've been involved in have had some connection to the outdoors - either there were plant particles on a suspect's clothes or evidence was found in the woods and it needed to be matched to another site - something along those lines.

posted on Sun, 01/18/2009 - 1:45pm
Anonymous's picture
Anonymous says:

hey I have always wnated to do something dealing with nature but im afraid of bugs - are there any plants that are scary or that you have to be careful around?

posted on Fri, 01/23/2009 - 11:52am
Anita Cholewa's picture

I don't think any plant is scary (:)) but there are lots that are poisonous (such as red baneberry) or that can cause rashes (such as poison-ivy) or that have nasty thorns (such as the hawthorns) or that can cause hallucinations.

posted on Fri, 02/06/2009 - 4:11pm
Anonymous's picture
Anonymous says:

Do plants have Circadian rhythms?

posted on Fri, 01/23/2009 - 4:25pm
Anita Cholewa's picture

Yes there are plants that have definite rhythms. Will Koukkari (now retired) at the University of Minnesota has done a lot of work on this subject. You will have to have a science librarian help you find details on this subject.

posted on Fri, 02/06/2009 - 4:12pm
JGordon's picture
JGordon says:

Or ask our other scientist on the spot, Van Gooch—he specializes in circadian rhythms!

posted on Fri, 02/06/2009 - 4:22pm
Rene's picture
Rene says:

how is it possable to identify a person from a crime scene from a flower?I thimk that it is really cool that you are a forensic botanist scientist. I like plants a lot

posted on Sat, 01/24/2009 - 5:01pm
Anita Cholewa's picture

It is not that we identify a person based on plants but that we can help pinpoint a suspect or victim to a crime scene. In addition to bullet casings and fingerprints, criminals often leave behind "trace evidence" - a fiber, or a hair, or other tiny bit of something. Sometimes this trace evidence include little (or big) pieces of plants, which can often be identified. Some plants are restricted in the places they can grow and so can be used to pinpoint locations where a suspect or victim had been. Sometimes the plants are commonly found in a lot of different places but can still be useful to tie a suspect's previous activity to certain localities (maybe a particular tree grew at the victim's house for example but not at the suspect's house).

posted on Fri, 02/06/2009 - 4:19pm