Canada goose
The Canada goose is our most familiar goose, although it is not actually native to the UK. A common and bold bird, it can be found around most parks, lakes, reservoirs and gravel pits.
Candlesnuff fungus
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.
Carline thistle
The Carline thistle produces distinctive brown-and-golden flower heads that look like a seeded thistle. These flowers are attractive to a wide range of butterflies, including the very rare Large blue.
Carrageen
This small reddish-purple seaweed grows in small branching fans on rocky shores. It is widely used in the food industry - and might have been used to produce your ice cream, beer or even jelly!
Carrion crow
The all-black carrion crow does not nest in colonies like the similar rook. It can be seen almost everywhere.
Cat flea
You are most likely to spot the cat flea if you have pets. It will feed on cats, dogs and people, although it can't live on us. It is a pest and needs to be controlled in the house for the comfort of pets and people.
Cattle egret
This small, white heron is an increasingly common sight in parts of the UK as it spreads north from continental Europe.
Cedar cup
This fascinating cup fungus is a lovely thing to stumble upon -should you be lucky enough!
Celery-leaved buttercup
Look out for the small, yellow flowers of Celery-leaved buttercup in wet meadows and at the edges of ponds and ditches. It flowers from May to September.
Cellar spider
You've probably spotted this long-legged spider hiding in the corner of a house or building.
Cetti's warbler
A dark, stocky warbler, the Cetti's warbler is most likely to be heard, rather than seen - listen out for its bubbling song among willow, marsh and nettles.
Chaffinch
The colourful and delightful chaffinch is a regular garden visitor across the UK. Look out for it hopping about on the ground under birdtables and hedges.