Asteraceae (B)

 The daisy family in Belgium:
 

With more than 30.000 species, the Asteraceae (daisy family) belong together with the Orchidaceae (orchids) to the top two of most species-rich plant families in the world. In Europe and Belgium as well, this large family is one of the most species-rich!

In our region, daisies and allies are exclusively herbaceous, but elsewhere they can form shrubs, lianas, even trees. Virtually all terrestrial habitats have several typical species belonging to this family, from tropical rainforests to mountain tundra. Except on Antarctica, daisy allies occur in every continent and every country in the world.

Some of the species will be familiar to you, such as sunflowers (Helianthus), daisies (Bellis), dandelions (Taraxacum), and thistles (tribe Cynareae). Others such as some tropical, tree-forming ragwort species (Senecio) seem already more exotic: daisy trees?! All members of this family share a very typical characteristic, namely the tubular small flowers which only grouped into inflorescences take the size and splendour which we expect from a flower; for instance, what we call a daisy flower is actually a composition of dozens of smaller flowers (florets): each torn away petal is factually one flower in itself. The family is further divided still above genus level based on the inflorescence. In a daisy, there are florets at the edge with conspicuous petals fused together, and others in the centre where these petals are missing. There are yet groups within the family where one or the other flower type are absent or where the petals may or may not be showy; think for example of a thistle in which no central disc exists.

 

 

 

Keywords (Latin):

 

Belgium, Asteraceae, Herbae, Hortus Botanicus Meise, Botanica.