What Is a Placenta in Plants? Where Seeds Attach Inside Fruit
A placenta in plants is the part of the ovary where seeds attach. The University of Minnesota’s Science of Plants defines the placenta as the part of an ovary where the funiculus attaches. It defines the funiculus as the stalk that links an ovule or seed to the placenta.
The short answer
The placenta is the tissue inside an ovary that holds the ovules, and later the seeds. In a pepper, it’s the pale core seeds cling to. Maine Extension says capsaicin is found in that white part. The way ovules attach is called placentation.
What is a placenta in plants?
It’s attachment tissue. NC State says the ovary contains ovules and each becomes a seed after fertilization. Each ovule hangs from the placenta on its funiculus, as the Minnesota text explains. Learn about seed parts in cannabis seed anatomy.
Where is the placenta in a pepper?
At the center. Maine Extension says capsaicin is in the white part inside peppers that the seeds attach to, also known as the placenta. Colorado State lists the parts of a jalapeño as exocarp, mesocarp, endocarp, placenta and seeds. It adds that capsaicin glands sit between the placenta and the endocarp and that seeds hold little capsaicin.
How does placentation differ between plants?
The Missouri Botanical Garden glossary describes several patterns in fused ovaries.
| Pattern | Where ovules attach | Source |
|---|---|---|
| Axile | Central axis, chambers split by walls | Missouri Botanical Garden |
| Free central | Free standing central column, no walls | Missouri Botanical Garden |
| Parietal | Ovary wall | Missouri Botanical Garden |
| Basal | Base of the ovary | Missouri Botanical Garden |
How to: step by step
- Slice a sweet pepper in half from top to bottom.
- Find the pale core at the stem end.
- Trace the pale ribs that run down the walls.
- Note where the seeds attach.
- Cut a tomato across and compare.
Troubleshooting
Pepper too hot: Colorado State says heat sits near the placenta, not the seeds.
Seeds hard to place: look for the funiculus, the stalk the Minnesota text describes.
Curious about other parts: read cannabis leaf anatomy and what roles do bees play in outdoor cannabis.
Seeds start at the placenta
Spot it in the next pepper you cut. Then see how flowers finish in the final weeks of flowering cannabis plants. Kind Seed Co shares more plant science notes for curious growers.
Sources
- Chapter 8: terms, The Science of Plants, University of Minnesota Libraries
- Glossary A to H, Angiosperm Phylogeny Website, Missouri Botanical Garden
- Growing peppers, mild to hot!, University of Maine Cooperative Extension
- Jalapeño peppers, Colorado State University Food Source Information
- Extension Gardener Handbook, chapter 3: botany, NC State Extension
FAQ
Is the pepper core the placenta?
Yes. Maine Extension calls the white part the seeds attach to the placenta.
Do all fruits have a placenta?
Seed bearing ovaries do. The University of Minnesota defines the placenta as the part of an ovary where the funiculus attaches.
What is placentation?
The Missouri Botanical Garden glossary uses it for the arrangement of the ovules in an ovary, such as axile or free central.
Is a plant placenta like an animal one?
Only by name. In plants it is the ovary tissue where the funiculus attaches, as the University of Minnesota defines it.
Do pepper seeds make the heat?
No. Colorado State says seeds can absorb some capsaicin but do not produce it.
