The five features that identify a seed
- Size — always photograph against a coin, a ruler or graph paper, because size is meaningless in a close-up.
- Shape — round, oval, kidney-shaped, angular, wedge-shaped, disc-like or winged.
- Surface — smooth, wrinkled, pitted, ridged, hairy, or covered in a papery coat.
- Colour and pattern — solid, mottled, speckled, striped or two-toned.
- The hilum — the scar where the seed joined the plant. Its position, shape and size are the single most diagnostic feature.
Seeds you are likely to be holding
| Seed | Size | Shape and surface | Giveaway |
|---|---|---|---|
| Apple and pear | 5-8mm | Tear-shaped, glossy dark brown | A pointed tip and a smooth, hard coat |
| Cherry and plum | 10-20mm | Round to oval, pale stone | A seam running down one edge |
| Sunflower | 10-15mm | Flat teardrop, striped black and white | The classic striped hull |
| Pumpkin | 15-20mm | Flat oval, creamy white | A raised rim all the way round the edge |
| Coriander | 3-4mm | Round, ridged, tan | Distinctive ribbed surface, citrus smell |
| Bean and pea | 8-15mm | Kidney-shaped, smooth | A large, obvious hilum on the inner curve |
| Tomato | 3-4mm | Flat, round, hairy, pale | The fuzzy surface is unmistakable |
| Poppy | 1mm | Tiny, kidney-shaped, pitted | Sold in bulk and easily mistaken for sand |
| Pine nut | 15-20mm | Elongated, pale, thin shell | A thin shell that splits along one edge |
| Castor | 10-15mm | Oval, mottled brown with a cap | Toxic. Never taste a mottled seed with a pale cap. |
Reading the hilum
The hilum is the scar left where the seed was attached to the fruit or the pod. On a bean it is a large, pale oval on the inner curve of the kidney. On a wheat grain it is a deep crease running the whole length. On a pine nut it is a small pale dot at one end.
Because the hilum is structural rather than cosmetic, it survives drying, storage and shipping. If you are identifying a seed from a mixed packet, the hilum is usually the feature that settles it.
How to photograph seeds so they can be identified
- Lay the seeds on a plain, matte surface — a sheet of white paper or card works best.
- Add a coin or a small ruler in the frame. Without a scale reference, a seed photo cannot be identified reliably.
- Photograph from directly above, with the light coming from the side so the surface texture is visible.
- Take one close-up of a single seed showing the hilum, and one wider shot showing several seeds together.
- If you know where the seed came from — a pod, a fruit, a tree — mention it in the context box. Origin is often the fastest route to a confident answer.
Seeds that should never be tasted
- Apple, pear, cherry, plum, peach and apricot seeds contain amygdalin, which releases cyanide when crushed or chewed. Swallowing one whole is harmless; chewing several is not.
- Castor seeds contain ricin and are seriously toxic. A few seeds can be fatal to a child.
- Laburnum, wisteria and lupin seeds are toxic, despite lupin being a food crop once properly processed.
- Any seed from a plant you have not identified with certainty. Identification first, always.
Seeds are small, but they carry a surprising amount of identifying information. The shape, the surface texture, the colour pattern and the scar where the seed attached to its parent plant are all stable features that do not change with the weather or the season.
This guide covers the seed features worth photographing, the families that can be recognised at a glance, and the seeds you should never taste.
Frequently Asked Questions
Sometimes. Distinctive seeds such as sunflower, pumpkin and pine nut identify easily. Small, plain seeds often identify only to family, because dozens of species share the same size, shape and colour.