What is a Capsule?
A capsule is a dry fruit that splits open when mature, releasing many seeds. Unlike fleshy fruits, capsules depend on wind, gravity, or explosive mechanisms for seed dispersal rather than animals eating them.
Structure and Opening
Key Characteristics
- Dry: Hard, papery, or woody (not fleshy)
- Dehiscent: Splits open at maturity
- Multi-seeded: Contains multiple seeds
- Multi-carpellate: Formed from 2+ carpels
Opening Methods
Loculicidal: Splits down the middle of each carpel Septicidal: Splits between carpels at seams Poricidal: Opens through pores (rare) Explosive: Forcibly ejects seeds
Costa Rican Capsule Trees
Ceiba (Ceiba pentandra)
- Large woody capsules 15-20cm long
- Split into 5 sections
- Release silky-haired seeds
- Float on wind like cotton
Pochote (Pachira quinata)
- Oval woody capsules
- Explosive dehiscence
- Seeds embedded in white fiber
- Similar to ceiba but smaller
Jacaranda (Jacaranda mimosifolia)
- Flat, round capsules
- Woody texture
- Contain many winged seeds
- Common ornamental street tree
Capsule vs. Other Dry Fruits
| Fruit Type | Opening | Seeds | Example | | ---------- | ----------- | ----- | -------------- | | Capsule | Splits open | Many | Ceiba, Pochote | | Follicle | One side | Many | Magnolia | | Legume | Two sides | Many | Beans | | Achene | Stays shut | One | Sunflower | | Samara | Stays shut | One | Maple (winged) |
Dispersal Strategies
Wind Dispersal
- Seeds with silky hairs (Ceiba)
- Winged seeds (Jacaranda)
- Light, numerous seeds
Gravity Dispersal
- Heavy capsules fall and break
- Seeds scatter locally
- Accumulate near parent
Explosive Dispersal
- Capsule builds tension
- Bursts open suddenly
- Flings seeds meters away
Why It Matters
Understanding capsules helps with:
- Identification: Capsule shape and size are diagnostic
- Seed collection: Timing harvest before dispersal
- Propagation: Knowing when seeds are mature
- Ecology: Understanding dispersal strategies
Field Recognition
Quick ID Tips:
- Look for dry, hard fruit
- Check for split lines or seams
- Count seed compartments
- Note if seeds have wings or hairs
- Observe on ground (already opened)
Best Observation Time:
- Late dry season for many species
- Watch for capsules starting to split
- Collect before complete dehiscence