Why the Arizona Popcorn-Flower is my favorite plant in the Park

By Lindy Brigham

I have been in the neighborhood since 1992, I live in Rancho Morado and am currently the RillitoBend Neighborhood President.  As a retired Plant Pathologist, my interest in plants is the many ways they have developed to avoid being eaten.
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​The Arizona Popcorn-flower, Plagiobothrys arizonicus, is in the Borage family. (“Most borage are of little or no economic value, but form a very conspicuous part of the early spring flora throughout the south-west.”
(Higgins, 1979))
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Other common names for the Arizona Popcorn-flower include popcorn flower, blood weed, bloodweed and lipstick plant. (Note that other plants also have the common name of popcorn flower or popcorn plant which is why it is important to know the scientific name that describes only one plant.)

​​The Popcorn-flower can first be seen the beginning of January in the Rio Vista Natural Resource Park. The leaves, which look a bit fuzzy, come out of the base in a radial pattern parallel to the ground. 

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​In the next stage, the leaves start to grow upward and the plant puts out shoots with tiny white  flowers.  The quarter in the middle picture gives a sense of scale.

​At this point you are probably saying, “So what’s the big deal about a tiny, seemingly nondescript plant I never notice?” 
 



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Well, these little plants spend a lot of energy making a beautiful chemical in their leaves and roots. If you look under the leaf—yes, you need to get down on the ground to see—you will notice that the edges of the leaf and the mid-vein are pinkish red.

Note my forefinger as a size reference for the flower which is about 3mm in diameter.

​Press a plant on a piece of paper and the dye from the roots, stems and leaves will come off on the paper.
 
The dye is in a class of chemicals called napthoquinones.  Napthoquinones occur in several Borages as well as in other plant families, and are commonly used as dyes in fabric and cosmetics.  Napthoquinones also have antimicrobial activity. (See 'READ MORE' below)

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​As the plants mature, they produce more stems and flowers and grow taller.  

​After the flowers have been fertilized, the seeds start to develop. The seeds are surrounded by a hard shell like a walnut so these structures are called 'nutlets'. You can see the dried flowers marked with a white F and below the nutlet is marked with a dark red N.

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​If there has been plenty of winter rain, they can grow up to 18 inches, but they usually reach 8 to 10 inches.

​Plagiobothrys and most other Borages in the Southwest are known as ephemerals. At the end of the season, they dry up and disappear from the landscape.  You would have never known they had been there if you hadn’t seen them.
 
In this picture, the red dye is still visible in the stems.

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​This section includes some fairly in depth information on the Borage of the southwest and the napthoquinones found in these  plants.

​Information on Plagiobothrys from several plant databases:

SWbiodiversitity.org (SEINet)
Southwest Desert Flora
Wildflower Search
Southeastern Arizona Wildflowers and Plants
San Diego State University - this has pictures of the seeds (nutlets)
Wayne's World - good pictures of nutlets and comparison with another plant called 'popcorn'

Here are some of the other Borages that also come up in Spring with the Plagiobothrys in the Rio Vista Park.
On the far left is Amsinckia, in the middle, Cryptantha, and on the far right, Lappula. 

More information on the Borages in the Southwestern United States is in Higgins, 1979
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The Japanese extract a napthoquinone they call shikonin from a related borage called Lithospermum erythrorhizon. Erythrorhizon means 'red root'.  The photo shows roots from a plant grown in a pot. ​

​As you can see, this chemical has significant anti-microbial activity. It is possible that Plagiobothrys (and other plants) make this chemical to protect themselves from bacteria and fungal pathogents. More about the possible role of the napthoquinones in plant defense against microorganisms can be found in Brigham et. al., 1998

I would like to thank the members of the RillitoBend Rambles Blog team (Mary Bird, Melanie Campbell-Carter, Estelle Stern-Eilers, and Vicky Stromee) for reviews and edits to the text.  All photographs are by the author.