Grindelia squarrosa

Curly-cup Gumweed - Grindelia squarrosa
Carbonate Creek, Black Range, New Mexico, USA
July 2015

Sometimes there is a statement which just leaves me with a “huh”?  The Vascular Plants of the Gila Wilderness entry for this species includes this statement: “Grindelia squarrosa is an erect herb with yellow disc flowers.  Until recently, Grindelia nuda, was recognized as a separate species lacking yellow ray flowers.  The two species have been lumped together, so now Grindelia squarrosa may or may not have ray flowers.”  I do not doubt the accuracy of this statement.  Unfortunately, I ran into a different source which had a photo of a plant which it described as Grindelia squarrosa with and without rays - on the same plant.  That is the source I saw first.  When I got to the Gila Wilderness site and found the above statement, it made no sense - how could anyone have classified a singular plant as two species?  As you can imagine there are numerous synonyms.  A more definitive discussion of the taxonomy of this species can be found at the Flora of North America site.  The species was first described by Frederick Traugott Pursh in 1813 as Donia squarrosa.  

I see now that, the first source I visited was in error.  What it was showing was Grindelia squarrosa (with the flower with rays) in flower and after anthesis (the “flowering” period).  After the rays of the flower fall off (or don’t fall off, if they were never there) - after anthesis - the flower cup becomes covered in a gummy- milky substance (pretty technical huh...- much better than the Gila Wilderness description of “gummy or resiny white substance”), shown in the photo below.

Curley-cup Gumweed is found in much of the United States and Canada, see range map to the right.  It is also found in Chihuahua, Mexico.


IMG_2944 - Version 2

Gallinas Canyon West Slope of the Black Range New Mexico, USA
Immediately above and below.
July 28, 2016


© Robert Barnes 2018