The true Christmas tree is the Norway spruce, which grows naturally from Scandinavia through to central Europe. Legend has it that St Boniface of Crediton, in Devon, was preaching in Germany 1,000 years ago and came across some pagans who were about to sacrifice a boy under the oak tree at which they were worshipping. In his anger, St Boniface cut down the tree, and a spruce tree instantly took its place. St Boniface took this to be a sign of Christianity, and thereafter his followers lit candles in its branches so he could preach by night. It may have been Martin Luther who first brought a Christmas tree indoors, but the British were comparatively late in borrowing the tradition. Prince Albert (Queen Victoria's German husband) introduced them in 1841. Candles were eventually replaced by electric Christmas lights when they were invented by the American Ralph Morris in 1895.
New Zealand Christmas tree
Also known as the Pohutakawa, this is a familiar tree in New Zealand's North Island. It grows to more than 20 metres high and has evergreen, leathery leaves. In midsummer it produces flowers with masses of bright crimson filaments - just in time for Christmas.
Tasmanian Christmas bells
These are the flowers of a low-growing plant with grass-like leaves that inhabits bogs and heaths on the island of Tasmania. Like the Pohutakawa, this species flowers around Christmas time at the height of the antipodean summer.
Christmas rose, or Alpine hellebore
This is a poisonous, large-leaved perennial that bears big, saucer-shaped white flowers around Christmas time. It grows naturally in Germany and south-eastwards to Slovenia, where it can be found in the mountains, often covered in snow.
Poinsettia, or Mexican flame leaf
Christmas is not in its name, but this plant is becoming increasingly associated with the festive season, its bright scarlet "flowers" enlivening many a seasonally-decorated room in Britain. The wild variety is found in Mexico, where it becomes a straggly shrub and flowers in winter. Its stunning red structures are actually leaf-like organs called involucral bracts, designed to attract insects to the otherwise inconspicuous flowers.
New varieties have been developed by horticulturalists. These have bracts of white, cream or pink. All are notoriously difficult to cultivate as they require trickery to make them flower again the following winter - the plants have to be subjected to 12-14 hours of darkness daily for two months to initiate flowering. Surprisingly, the poinsettia is a close relative of the spurges, poisonous weeds of flowerbeds and waste ground in Britain and large, spiny, cactus-like species in Africa. All members of the family exude a toxic white sap when damaged.
A species of shrub found in Brazil, where it produces funnel-shaped purple flowers in December.
Christmas berry tree
A tree with graceful arching stems covered in red berries at Christmas.
It grows in Venezuela, Argentina and southern Brazil.