Seedbox, Bushy Seedbox, Bushy Waterprimrose

Ludwigia alternifolia

lud-WIG-ee-uh  al-tern-ee-FOH-lee-uh

Synonyms of Ludwigia alternifolia (15) (Updated on 12-21-23 from Plants of the World Online): Isnardia alternifolia (L.) DC., Isnardia alternifolia var. salicifolia (Poir.) DC., Isnardia alternifolia var. uniflora (Raf.) DC., Isnardia aurantiaca DC., Ludwigia alternifolia var. linearifolia Britton, Ludwigia alternifolia var. pubescens E.J.Palmer & Steyerm., Ludwigia alternifolia var. typica Munz, Ludwigia angustifolia var. ramosissima (Walter) Poir., Ludwigia aurantiaca Raf., Ludwigia macrocarpa Michx., Ludwigia microcarpa Link, Ludwigia pruinosa Raf., Ludwigia ramosissima Walter, Ludwigia salicifolia Poir., Ludwigia uniflora Raf.

Ludwigia alternifolia L. is the accepted scientific name for this species of Ludwigia. The genus and species were described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

As of 12-21-23 when this page was last updated, Plants of the World Online lists 87 species in the Ludwigia genus. It is a member of the plant family Onagraceae with 22 genera. Those numbers could change as updates are made on POWO.

The distribution map for Ludwigia alternifolia is from Plants of the World Online. Areas in green are where the species is native. The map on the USDA Plants Database also includes the state of Colorado but without any county data. 

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 TO HELP WITH A BETTER POSITIVE ID.

I found this good-sized colony of Ludwigia alternifolia in the back of the farm by the pond on September 1 in 2019 while I was wildflower hunting. The first thing that caught my attention was the square-like seed pods. There were barely any flowers to be found.

The stems of the Ludwigia alternifolia can be light green, red, brown, or even nearly white. As the plant ages, its bark will split near the base of the stems. Most of the plants had multiple branches. Ummm… The yellow flowers in the photo are not from this species… 🙂

Single yellow flowers emerge from the axils from the upper leaves on short pedicles from green bractlets that may have short hairs. The yellow flowers have 4 petals, 4 light green sepals, 4 short stamens, and a pistol with a short style. The problem with finding flowers is that they only last for a single day and fall off easily.

The lance-shaped, hairless leaves grow in an alternate pattern along the stems. The leaves can grow to 4” long and 3/4” wide, are narrowly lanceolate,  rounding at the tips, tapering at the base with short petioles. The leaves are light to medium green.

The stems were mostly hairless but some had a fuzzy appearance…

The odd seed capsules are nearly square the break into 4 parts to release the seeds. 

<<<<2020>>>>

I intended to hunt for the Ludwigia alternifolia earlier in the season but I was fairly busy over the summer. I have to walk through the tall grass in the hayfield to get to the back of the farm which can be very exhausting so I waited until the hay was cut.

<<<<2023>>>>

It seems very hard for me to get photos of the flowers of this species. I didn’t do much wildflower hunting in 2023 because of the heat and drought. Maybe I can do a better job in 2024…

I have enjoyed photographing and learning about the many wildflowers growing on the family farm and in other areas. I have grown over 500 different plants and identified over 250 wildflower species (most have pages listed on the right side of the blog). 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 horticulturalist 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)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
MISSOURI BOTANICAL GARDEN
DAVE’S GARDEN
MISSOURI PLANTS
iNATURALIST
WILDFLOWER SEARCH
USDA PLANTS DATABASE
ILLINOIS WILDFLOWERS
IOWA PLANTS
LADY BIRD JOHNSON WILDFLOWER CENTER
KANSAS WILDFLOWERS AND GRASSES
GO BOTANY

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 thousands of species to keep up with. Accepted scientific names change periodically and can be hard to keep with. 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. 🙂