THE APIACEAE (UMBELLIFERAE) FAMILY
A large, important, succesful family of herbs sharing an easily identifiable common characteristics, their famous upside down ‘umbrella flowers’ on stalks which fill our hedgerows and bridleways with an abundant profusion of summer colour. They have provided us with our most famous root crops, vegetable and medicines, saving and sustaining millions of human and animal lives. They do have a darker side, many are poisonous, fortunately few deaths occur now. Most are native and common, having colonised every habitat in Britain, bar upland moors, salt marshes and deep shade. Some, introduced by the Romans, have become naturalised and common here, fewer are casuals and garden escapes. They are generally well known for being indistinguishable from each other, but with reference to habitat, flowering time, leaf shape and aroma they can be easily identified.
* * * CLASSIFICATION * * *
The family Apiaceae belongs in the Apiales order. A large worldwide family containing 3700 species in 434 genera, concentrated in the N. Northern temperate region. They are herbs, but Bupleurum has a number of shrubby species, woody members occur in Africa the largest is Steganotaenia, a 12m high tree. The family contains 4 sub families Mackinlayoideae, Azorelloideae, Saniculoideae & Apioideae. There is much overlap regarding diagnostic characteristics and so each genera usually contain one species, and are said to be monotypic. A concise ‘History of Classification’ is given by Lincoln Constance 1971. The current state of classification of the family and sub families is in flux due to new methods of categorisation using molecular phylogenetic analyses. I have attempted to update this info as of 2012.
* * * IDENTIFICATION * * *
Is much easier than previously thought. First consider its habitat and flowering time, then
the presence or absence of bracts, the number and length of the rays, the shape and degree of dissection of the leaves, aroma is important too. If the plant has not seeded yet, it is worth waiting for, as every genera has an entirely different shaped seed (with some exceptions). If picking for culinary or medicinal reasons please refer to a specialist, as plants can be deformed or mistaken and result in illness or death if consumed incorrectly, for which actions the author takes no responsibility. (I have myself innocently picked leaves of an umbel, due it's pleasant parsley smell, for my salad, only to identify it later as Hemlock Water Dropwort, mind you it did taste great). For truly accurate identification seeds must be seen under a microscope or the nucleic chromosomal number established.
* * * POLLINATION * * *
The umbels are unique in their floral uniformity. They encourage free pollination
by unspecialised pollinators, an interesting evolutionary adaptation. The effects of
this promiscuous pollination allow it to increase its natural distribution and thus
colonise new habitats easily.
The majority of insects are attracted by the copious quantities of nectar which is
prolonged when the stigmas become receptive, some time after the anthers have ripened. The styolopodium is also often large and brightly coloured attracting by sight. In others
the outer petals found on the peripheral rim are larger and said to radiate, the inner
disc may have smaller petals and be coloured yellow or purple, thus giving the effect
of a single composite flower. This acts as a decoy for insects that might not normally
visit Apiaceae.
300 pollinators and visitors have been recorded, the commonest being Diptera (flies gnats, thrips, mosquitoes), smaller Coleoptera beetles and Hymenoptera (ants and small tonuged bees) In a few species the basal half of the infolded petal is erect and forms a corolla tube which limits access to short tongued Hymemnoptera.
There are usually male flowers in lateral umbels below the terminal hermaphrodite
umbel. The hermaphrodite flowers contain an extra pollen reservoir ensuring the success
of these early flowering parts to pollinate. The male flowers later ensuring outbreeding;
discouraging self pollination.
* * * SEED DISPERSAL * * *
Hooked spines on many fruits act as a special aid for dispersal by mammals. Others
have broad lateral wings, for dispersal by the wind. The aquatic species have fruits
with hollow spongy interiors, allowing them to float.