Laburnum

Laburnum species

ID check

  1. Leaves are alternate in arrangement and divided into separate leaflets.
  2. There are 3 leaflets radiating from the leaf stalk.

Description

Laburnum tree

Laburnum tree © Andrew Dunn, Creative Commons Attribution-Share Alike 2.0 Generic

Tree

Small and slender trees up to 7m tall, with arching branches.

Twigs

Greyish-green with silky hairs.

Leaves

With 3 elliptical leaflets, greyish-green and with silky hairs.

Flowers

Pea-like and yellow. In loosely hanging clusters, 10–40cm long.

Fruit

A pod 4–6cm long.

Notes

The split pods, with black seeds still attached to the pale inner surfaces, remain on the tree well into winter. The seeds are poisonous.

Images

Laburnum tree leaf

Laburnum tree leaf divided into 3 leaflets.

© Università di Trieste, Dipartimento di Biologia. Photo: Andrea Moro
Laburnum tree flowers

Laburnum tree flowers.

© Università di Trieste, Dipartimento di Biologia. Photo: Andrea Moro
Laburnum tree

Laburnum tree.

© Andrew Dunn, Creative Commons Attribution-Share Alike 2.0 Generic

Diagrams

These diagrams explain some of the important tree and plant parts.

Flower

Diagram of a flower showing the stigma, stamen, style, petal and sepal

Leaf parts

Diagram of a leaf showing the apex, margin, midrib, vein and stalk

Leaf shapes

These diagrams show the different leaf shapes you might come across on your survey. Leaf shapes are important for identifying trees.

Palmate leaf
A palmate leaf - the leaflets extend from a single point, like fingers from a hand
Palmately lobed leaf
Palmately lobed leaf - the lobes are arranged on both sides of the stalk like a feather
Pinnate leaf
Pinnate leaf - the leaflets are arranged on both sides of the stalk like a feather
Pinnately lobed leaf
Pinnately lobed leaf - the lobes are arranged on both sides of the stalk like a feather

Leaf arrangements

The way leaves are arranged on a stem can be important for identifying trees.

Opposite leaves
Opposite leaf arrangement
Alternate leaves
Alternate leaf arrangement

Glossary

These definitions explain some of the trickier words and phrases used in these pages.

Alternate – the arrangement of leaves on a stem - the leaves attach at different but alternating points, rather than opposite points.

Anther – the part of the stamen that contains pollen.

Apex – the top or end; the tip of a leaf for example.

Bract – a leaf-like structure, usually found below the flower or fruit.

Bud scale – usually a type of modified leaf that encloses and protects a bud.

Catkin – slender inflorescences made up of small flowers, usually reduced to the male and female parts. Catkins are typical of wind-pollinated trees.

Coniferous – trees that have cones, and needle or scale-like leaves.

Crown – in a tree, everything above the trunk.

Deciduous – a tree that sheds its leaves all at once in the autumn.

Evergreen – a tree that retains its leaves all year round.

Girth – the circumference of something, like the trunk of a tree.

Gland (of a leaf) – a small organ on a leaf that gives out oils or similar substances.

Inflorescence – the arrangement of all the flowers on a tree. The shape is used to help identify the plant.

Key – a tool used to identify groups and species of living things.

Leaflet – a subdivision of a leaf - it may look like a leaf but is attached to the leaf stalk or midrib, not to the shoot.

Lobe – a rounded or pointed section of a leaf, not divided into a leaflet.

Margin – the edge of a leaf.

Midrib – the central vein of a leaf.

Native – a tree that occurs naturally in an area, as opposed to a non-native tree that has been introduced.

Opposite – the arrangement of leaves on a stem - the leaves attach in pairs at the same point, opposite each other, rather than attaching at alternate points.

Palmate – a leaf shape in which the lobes or leaflets radiate from a single point, like fingers from a hand.

Petals – usually larger and more brightly coloured than sepals.

Pinnate – a leaf shape in which the lobes or leaflets are arranged on both sides of the stalk or midrib like a feather.

Pollarded – when the upper branches of a tree have been cut back to encourage new growth.

Sepals – the outermost parts of a flower which cover and protect the flower when it is in bud. They are usually green.

Side shoots – short, spur-like shoots growing from the main shoots.

Spike – an elongated cluster of flowers; a type of inflorescence.

Stalk – the structure that supports the blade of a leaf.

Stigma – the part at the end of the style. It is covered with a sticky substance that pollen adheres to.

Stipule – a small, leaf-like structure, found where the leaf connects to the stem.

Style – a tube-like structure in the centre of a flower that supports the stigma.

Trunk – the woody stem of a tree, before the branches.

Urban forest – the trees in our towns and cities.

Whorl – 3 or more leaves or needles circling around a stem.