A notoriously poisonous plant, hemlock produces umbrella-like clusters of white flowers in summer. It can be found in damp places, such as ditches, riverbanks and waste ground.

A small and delicate plant of chalk grasslands, Fairy flax can be seen in bloom from May to September - look out for its nodding, white flowers.

Arrowhead is an aquatic plant of shallow water and slow-moving waterways. In bloom over summer, it displays small, white flowers, but it is the arrow-shaped leaves that are most distinctive.

The candlesnuff fungus is very common. It has an erect, stick-like or forked fruiting body with a black base and white, powdery tip. It grows on dead and rotting wood.

Look for the star-like, feathery, white flowers of Bogbean in ponds, fens, bogs and marshes. It is so-named because its leaves look like those of broad beans.

Wild privet is a shrub of hedgerows, woodlands and scrub, but is also a popular garden-hedge plant. It has white flowers in summer and matt-black berries in winter that are very poisonous.

Mae'r gwyn bach yn ymwelydd gardd cyffredin. Mae'n llai na'r gwyn mawr tebyg, ac mae ganddo lai o ddu ar flaen ei adenydd.