Native Plants
Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
rate this answer
Thursday - July 07, 2011
From: Grinnell, IA
Region: Midwest
Topic: General Botany, Plant Identification
Title: Difference between Erigeron strigosus and E. annuus
Answered by: Nan Hampton
QUESTION:
How can you tell the difference between Erigeron strigosus or Erigeron annuus. Does one have more flowers on it than the other? Thanks.ANSWER:
As you have already discovered, I'm sure, the differences are not obvious. In fact, they are VERY subtle. Erigeron strigosus (Prairie fleabane) was once considered a subspecies of Erigeron annuus (Daisy fleabane). (Erigeron annuus ssp. strigosus is the synonym for the accepted name Erigeron strigosus var. strigosus. See the entry from ITIS–Integrated Taxonomic Information System.)
You can read a description of E. strigosus and a description of E. annuus from eFlora.org, the online version of Flora of North America. There are many technical botanical terms used in the description. If you have James Harris' excellent book, Plant Identification Terminology, you shouldn't have any problem working your way through the terms. If you don't have Harris' book, here are a few sites that should help you. For leaf shape, try the Berkeley Echo Lake Camp Leaf Shape Terms and Leaf Shapes and Arrangements from The Seed Site. You can find a very good list of Botanical Terms on the Calflora.net site. Reading through and comparing the descriptions, you can see there are small differences in the types of hairs on the stems and leaves, the leaf shapes and whether the leaves persist during flowering. You will also note there is considerable overlap in sizes and numbers of structures. E. annuus is listed as having 5–50+ flower heads and E. strigosus is shown as having 10–200+, but still there is some overlap. Just to complicate things more, please note the statement at the end of the description of E. annuus:
"Apparent intermediates between E. annuus and E. strigosus are encountered."
If you go to the 'parent' page for Genus Erigeron on eFloras, you will see that the the genus is divided into 23 Groups. E. annuus and E. strigosus are part of Group 4. The key to Group 4 of Erigeron spp. summarizes the differences in the two species and is a bit easier to get through; but, as you will see, there is still overlap in the descriptions and you are going to need a magnifying glass to see some of the differences.
Good luck in distinguishing between the two!
From the Image Gallery
More Plant Identification Questions
Native flowers versus non-natives
June 30, 2014 - Native flowers versus non-natives. What guidelines do use for identification. I come across flowers in different habitats and can't identify them as natives.
Also, how do you attach a image to a ...
view the full question and answer
Carolina allspice (Calycanthus floridus) in Jasper TX
October 27, 2011 - Carolina allspice (calycanthus floridus) grows in my yard in East Texas. It is native to the eastern U.S., but I notice there is a variety whose distribution extends through Louisiana. Since I live in...
view the full question and answer
Plant identification
October 06, 2009 - We have a large bush type plant, about 4 feet tall, fragant voilet flowers, large dark green leaves and spiney seed pods (about the size of golf balls) that have many seeds inside. They started growi...
view the full question and answer
Plant identification
August 11, 2008 - Just after the last little rain we got, I noticed a small, inconspicuous plant in my front yard that was sprouting a structure that looks for all the world like a pitcher plant. It is not, however, an...
view the full question and answer
Identification of small tree in McKinney TX with puffy red/pink bloom
May 23, 2011 - Looking for info on McKinney area sm/med size tree found at water's edge that has a puffy rd pink bloom. Thanks.
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |