Strophostyles helvola (Amberique Bean, Etc.) on 8-8-22, #903-13.

Amberique Bean, Annual Wild Bean, Missouri Fuzzy Bean, Sand Bean, Wild Bean, Trailing Fuzzy Bean

Strophostyles helvola

stro-foh-STY-leez  HEL-vol-a

Synonyms of Strophostyles helvola (25) (Updated on 12-18-23 from Plants of the World Online): Cajanus helvolus (L.) Spreng. (1826), Dolichos angulosus DC. (1825), Dolichos helvolus (L.) Nutt. (1818), Dolichos parabolicus Nutt. (1818), Dolichos vexillatus Nutt. (1818), Glycine angulosa Muhl. ex Willd. (1802), Glycine helvola (L.) Elliott (1818), Glycine peduncularis Muhl. (1813), Glycine peduncularis var. parabolica Muhl. ex W.P.C.Barton (1815), Glycine pedunculosa Raf. (1808), Glycine virginica Spreng. (1801), Phaseolus angulosus Ortega (1797), Phaseolus diversifolius Pers. (1807), Phaseolus helvolus L. (1753), Phaseolus helvolus var. missouriensis (S.Watson) Britton (1894), Phaseolus parabolicus Nutt. ex W.P.C.Barton (1818), Phaseolus peduncularis W.P.C.Barton (1818)(nom. superfl.), Phaseolus peduncularis var. parabolica (Muhl. ex W.P.C.Barton) W.P.C.Barton (1818), Phaseolus trilobus Michx. (1803)(nom. illeg.), Phaseolus vexillatus Walter (1788)(nom. illeg.), Strophostyles angulosa Elliott (1823), Strophostyles angulosa var. missouriensis S.Watson (1890), Strophostyles helvola var. missouriensis (S.Watson) Britton (1897), Strophostyles peduncularis Elliott (1823)

Strophostyles helvola (L.) Elliott is the accepted scientific name for this species. The genus and species were named and described as such by Stephen Elliott in the second volume of A Sketch of the Botany in South Carolina and Georgia in 1824. It was first named and described as Phaseolus helvolus by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753.

Although Mr. Linnaeus actually named the species Phaseovolus helvulus, the name S. helvola was conserved by the Committee for Spermatophyta as was the name “helvolus”.  It was also found that the conserved “type” (from 1896) was actually identified as Strophostyles umbellata. The committee successfully proposed the replacement of Verdcourt’s type with another conserved type corresponding with the current usage of S. helvola. To read this information on the Natural History Museum Data Portal click HERE.

As of 12-18-23 when this page was last updated, Plants of the World Online lists 3 species in the Strophostyles genus. It is a member of the plant family Fabaceae with 793 genera. Those numbers could change as updates are made on POWO. 

The above distribution map for Strophostyles helvola is from the USDA Plants Database. Areas in green show where the species is native. The map on Plants of the World Online isn’t up to date. POWO gets their maps for North America from Flora of North America but that site doesn’t include the plant family Fabaceae yet. FNA will be releasing their information on the Fabaceae family very soon then POWO will update their maps. 

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND FOR A BETTER POSITIVE ID.

I was walking along the fence next to the road in the front pasture on August 2 in 2019 when I spotted a few weird flowers. They were an off-pinkish color and looked a little like sweet peas. Then I noticed the leaves were like beans instead of peas. I took several photos but the ones of the flowers were blurry, so I went back the next day for more. I took several more photos and most of them were blurry as well. It seems they don’t like their photos taken… I did get a few good enough to submit to iNaturalist for an ID which suggested Strophostyles helvola. I cross-referenced the name on the Missouri Plants website which turned out to be correct. The species is very similar to S. umbellata, but S. helvola has longer calyx bracts… 

There are more photos at the bottom of the page under the links for further information.

Strophostyles helvola is a trailing or climbing annual wildflower that is native to the central part of North America eastward. It says online they prefer part sun, but where they grow along the fence here, they are in full sun. They can be found in forests, along stream and pond banks, pastures, open disturbed areas, etc… They like moist conditions in sandy, loamy, or even gravely soil, but are likely somewhat drought-resistant as well. The first year I found it in the fence row, it was almost to the top of the hill. Each year it has relocated farther down the hill close to an area where water stands after a good rain. They prefer other plants (or fences) to climb on, but they will also sprawl along the ground.

Like typical pole beans we grow in the garden, the stems of S. helvola are sort of thin and twine from left to right (counterclockwise), looking from the top. The stems are somewhat hairy (pubescent) and can be light green, grayish-green, dull red, or reddish-purple. They grow anywhere from 3-8 feet in length. Vines that grow along the ground sometimes root at leaf nodes.

The trifoliate leaves grow in an alternate pattern along the stems. Some plants of the species may have deeply lobed leaves, while in others, the lobes are nearly unnoticeable (like here on this farm). Sometimes the lobes look like a small wavy indention in the margin. The lobes, being variable, are not a deciding factor with the species. The Missouri Plants website shows photos of both. Obviously, there are three leaflets per trifoliate leaf each with a small petiole (nearly sessile), the terminal leaflet and petiole being somewhat longer.

I need to look closer, but there are a pair of stipules at the base of the petiole where they join the stem. The leaflets are somewhat ovate-triangular, tapered or rounded at the base, tapering to a sharply or bluntly pointed tip. The tips sometimes have an extension of the midvein. The upper surface is dark green and the undersurface is somewhat lighter. Both surfaces can have very tiny appressed hairs or be glabrous (hairless). 

Clusters of 3-5 flowers appear at the end of long peduncles (flower stems)  that grow from the axils of some of the leaf nodes. The flowers are subtended by tubular calyces with bractlets as long or longer than the calyces tube. The end of the tube is somewhat lobed. Strophostyles umbellata is very similar but has much shorter calyx bracts. Information online says the flowers are pinkish purple to pink and fade to a yellowish color. Hmmm… I would say the flowers on the farm are “pinkish” but not pink.

The flowers are “papilionaceous” and have a banner, wings, and keel with a beak-like tip… Kind of like the Sweet Pea (Lathyrus latifolius) and other members of the plant family Fabaceae. Around here, this species produces flowers from June-October. 

Fertile flowers are replaced by a cylindrical seed pod that will contain 4-10 sort of rectangular seeds. The pods split open when dry and ready.

I am always taking a lot of photos and finding find new species. Sometimes it takes a couple of years to get descriptions written, and when I do I learn about features I need to get close-ups of. For this species, I need better close-ups of the flowers and calyx brackets, leaves, and stems. I took a lot of flower photos but most were blurry. Some species and colors are tough!

I have enjoyed photographing and learning about the many wildflowers growing on the family farm and in other areas. The farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF MISSOURI (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
USDA PLANT GUIDE
DAVE’S GARDEN
MISSOURI PLANTS
iNATURALIST
WILDFLOWER SEARCH
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
GO BOTANY
LADY BIRD JOHNSON WILDFLOWER CENTER
FRIENDS OF THE WILDFLOWER GARDEN
MARYLAND BIODIVERSITY PROJECT
CLIMBERS-UNIVERSITY OF MICHIGAN

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂

MORE PHOTOS…