What Is a Hypanthium? The Fleshy Flower Base in Apples and Pears
A hypanthium is a flower base that can swell into fruit flesh. The Virginia Master Gardeners fruit table says a pome, such as an apple or pear, is an accessory fruit with a fleshy hypanthium around the core.
The short answer
In apples and pears, the part you eat is mostly hypanthium, not ovary. The core holds the seeds, wrapped in fleshy hypanthium. So a pome is an accessory fruit, unlike a cherry or plum, which is a drupe from a single carpel.
What is a hypanthium?
It’s tissue at a flower’s base that becomes part of the fruit in pomes. NC State Extension explains that a fruit is a ripened ovary, so any flesh from outside the ovary counts as an accessory part. See cannabis leaf anatomy for plant part names.
How does it look in apples and roses?
Cut an apple across and you’ll see the core in the middle, wrapped in hypanthium flesh, per the Virginia fruit table. On rugosa rose, NC State Extension describes red to orange, cherry like hips about 1 inch wide with 20 to 120 achenes inside. Pollinators that set these fruits are in what roles do bees play in outdoor cannabis.
What about rose hips?
NC State says rugosa hips are used for jams, jellies and tea. Extension sources don’t say the hip is a hypanthium, so we don’t claim it. Leave flowers on the plant to see hips form, and pair roses with other plants as in companion plants when growing marijuana.
Fruit types compared
| Fruit | Type | Source |
|---|---|---|
| Apple, pear | Pome with hypanthium | Virginia MG |
| Cherry, plum | Drupe | Virginia MG |
| Strawberry | Ripened receptacle | NC State |
| Rugosa hip | Holds achenes | NC State |
Sources: NC State Extension, Master Gardeners of Northern Virginia.
How to: step by step
- Pick an apple or pear and an open flower.
- Find where sepals, petals and stamens attach.
- Look for the base below them.
- Cut the fruit in half lengthwise.
- Compare the core with the flesh around it.
- Watch a rose flower ripen into a hip.
Troubleshooting
Can’t see the base: small flower. Cut it lengthwise.
Core and flesh look alike: unripe fruit. Use a ripe one.
No hips: deadheading. Leave the flowers on.
Kind Seed Co shares more botany notes on the blog.
Sources
- Extension Gardener Handbook, chapter 3: Botany, NC State Extension
- Rosa rugosa (rugosa rose), NC State Extension Gardener Plant Toolbox
- Types of fruit (table), Master Gardeners of Northern Virginia (Virginia Cooperative Extension volunteers)
FAQ
Is the hypanthium part of the fruit?
In pomes, yes. The Virginia Master Gardeners fruit table says a pome is an accessory fruit with a fleshy hypanthium around the core.
Do all flowers have a hypanthium?
Extension sources don't say how widespread it is. They name it only for pome fruits such as apple, pear, chokeberry and serviceberry.
Is a rose hip a fruit?
NC State Extension says rugosa rose hips are red to orange, about 1 inch and cherry like, with 20 to 120 seeds (achenes) inside. The sources don't call the hip a hypanthium.
What other plants have a floral cup?
The Virginia fruit table names apple, chokeberry, pear and serviceberry as pomes with a fleshy hypanthium.
Is a strawberry the same thing?
No. NC State Extension says a strawberry is a ripened receptacle, the expanded tip of the flower stalk, not a hypanthium.
