Taxonomy of Flowering Plants - LECTURE NOTES - Spring, 1998
Hugh D. Wilson - rm. 306, Butler Hall
23 March 1998
The Rosidae
Family Overview - The Apiales
Apiaceae (Umbelliferae) - the Carrot Family
 
          
Diversity:  Mostly herbs - often perennial - about 300 genera and over 3,000 species with highest diversity in northern, temperate parts of the world and tropical uplands.  Important commercially as a food resource, Daucus carota (carrot) and Apium graveolens (celery), and aromatic compounds that are often used as spices:  parsley (Pteroselinum hortense), dill (Anethum graveolens), coriander (Coriandrum sativum), caraway (Carum carvi).  This usage masks the fact that most species of this family, such as Conium maculatum - (poison hemlock) are highly toxic.
 
Distribution:  Worldwide, but mostly in the northern hemisphere with extensions into the tropics at higher elevations.  We have 42 genera with 78 species in Texas, including many common, conspicuous, elements of the local flora.

Floral structure:

 
 Significant features:  Leaves alternate but often compound or deeply dissected and usually with distinctive expansion of the petiole base that sheaths the shoot at the node.  Stems often 'bamboo-like' with hollow internodes.  Flowers small and pentamerous but usually organized into compound umbels, an excellent key character for the family that is linked to the conserved name.  As is the case with many 'well marked' families, identification to genus and species is difficult and based on features of the gynoecium.  This is bicarpellate and biloculate with a single ovule per locule.  The styles often emerge from an expanded or enlarged base at the top of the ovary (stylopodium) and the gynoecium separates into two carpellary units at maturity (schizocarp), with each unit known as a mericarp.  Outer surface of each mericarp often carries ridges and 'oil tubes' that contain volitale oils (caraway 'seeds' are really mericarps) and the separated mericarps often remain suspended from the floral axis via thin connecting structures known as carpophores.  The common surface of mericarps or the area of separation is known as the commissure.

 
 

 Polytaenia nuttalliieum  - at anthesis with compound leaves sheathing at the base (left) and detail of the compound umbel (right)
 

 
 

 Winged mericarps of Polytaenia nuttalliieum  - prior to separation (left) and after (right) showing commissure and carpophores. 
 
 
Coriandrium sativum (coriander) - overview from Kohler's Medicinal Plants (1), plants in flower (2), inflorescences (3) and maturing gynoecia (4)
 
1
2
3
4
 
Anethum graveolens (dill):
 
Plant in flower
Inflorescence (compound umbel)
Umbellet
Infructescence

More information on the Apiaceae or Umbelliferae

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