April

Oaks

by Clare Coleman

You need to be able to tell the two species of British Oak from one another in order to record either in your WFS diary. So which is which?

The problem for many beginners is that hybrids between English or Pendunculate Oak (Quercus robur) and Sessile Oak (Quercus petraea) are common - known as Quercus x rosacea. Beginners may feel rather overwhelmed by mention of plant hybrids. But it is the existence of hybrids that makes identification difficult. Generally, hybrids are intermediate in characters.

Quercus x rosacea often looks closer to Quercus robur, usually having a slightly lobed base to the leaf but has a leaf stalk, like Q. petraea

Oaks are a species that require you to look at a combination of characters to get a correct identification.

  Quercus robur Quercus petraea
Habitat Wet Loams and clays Lighter sandy soils
Acorns Stalked not stalked
Leaf stalk (or petiole) None Stalked
Hairs on underside of leaf None Stellate hairs along mid-rib
Base of leaf Distinct lobed base known as auricles Tapering base without auricles

Further reading and references

To get an idea of what the hybrid Oak looks like, the illustrations on p75 of Plant Crib (1998) are excellent.