Some points about Poinsettias
Poinsettias are popular plants at Christmas. Biologists know that the distinctive red or other coloured parts are not in fact flowers but bracts - modified leaves next to the actual flower itself (see below).
They are short day plants, which means they need the stimulus of restricted day length before they develop the flowers and coloured bracts - the reason why plants kept to the next year do not usually colour up in the same way.
Poinsettia is not their true scientific name - it was given in honour of the first US ambassador to Mexico, a plant lover who introduced it to horticulture. It belongs to the spurge family - its proper name is Euphorbia pulcherrima
From the National Christmas Tree Association (NCTA) - USA
History of Christmas Trees
Tree Varieties
