Apiaceae


Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus Apium and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plants, with more than 3,700 species in 434 genera including such well-known and economically important plants such as ajwain, angelica, anise, asafoetida, caraway, carrot, celery, chervil, coriander, cumin, dill, fennel, lovage, cow parsley, parsley, parsnip and sea holly, as well as silphium, a plant whose identity is unclear and which may be extinct.
The family Apiaceae includes a significant number of phototoxic species, such as giant hogweed, and a smaller number of highly poisonous species, such as water hemlock, poison hemlock, water dropwort and spotted cowbane.

Description

Most Apiaceae are annual, biennial or perennial herbs, though a minority are woody shrubs or small trees such as Bupleurum fruticosum. Their leaves are of variable size and alternately arranged, or with the upper leaves becoming nearly opposite. The leaves may be petiolate or sessile. There are no stipules but the petioles are frequently sheathing and the leaves may be perfoliate. The leaf blade is usually dissected, ternate or pinnatifid, but simple and entire in some genera, e.g. Bupleurum. Commonly, their leaves emit a marked smell when crushed, aromatic to foetid, but absent in some species.
The defining characteristic of this family is the inflorescence, the flowers nearly always aggregated in terminal umbels, that may be simple or more commonly compound, often umbelliform cymes. The flowers are usually perfect and actinomorphic, but there may be zygomorphic flowers at the edge of the umbel, as in carrot and coriander, with petals of unequal size, the ones pointing outward from the umbel larger than the ones pointing inward. Some are andromonoecious, polygamomonoecious, or even dioecious, with a distinct calyx and corolla, but the calyx is often highly reduced, to the point of being undetectable in many species, while the corolla can be white, yellow, pink or purple. The flowers are nearly perfectly pentamerous, with five petals, sepals, and stamens.
The androecium consists of five stamens, but there is often variation in the functionality of the stamens even within a single inflorescence. Some flowers are functionally staminate while others are functionally pistillate. Pollination of one flower by the pollen of a different flower of the same plant is common. The gynoecium consists of two carpels fused into a single, bicarpellate pistil with an inferior ovary. Stylopodia support two styles and secrete nectar, attracting pollinators like flies, mosquitoes, gnats, beetles, moths, and bees. The fruit is a schizocarp consisting of two fused carpels that separate at maturity into two mericarps, each containing a single seed. The fruits of many species are dispersed by wind but others such as those of Daucus spp., are covered in bristles, which may be hooked in sanicle Sanicula europaea and thus catch in the fur of animals. The seeds have an oily endosperm and often contain essential oils, containing aromatic compounds that are responsible for the flavour of commercially important umbelliferous seed such as anise, cumin and coriander. The shape and details of the ornamentation of the ripe fruits are important for identification to species level.

Taxonomy

Apiaceae was first described by John Lindley in 1836. The name is derived from the type genus Apium, which was originally used by Pliny the Elder circa 50 AD for a celery-like plant. The alternative name for the family, Umbelliferae, derives from the inflorescence being generally in the form of a compound umbel. The family was one of the first to be recognized as a distinct group in Jacques Daleschamps' 1586 Historia generalis plantarum. With Robert Morison's 1672 Plantarum umbelliferarum distribution nova it became the first group of plants for which a systematic study was published.
The family is solidly placed within the Apiales order in the APG III system. It is closely related to Araliaceae and the boundaries between these families remain unclear. Traditionally groups within the family have been delimited largely based on fruit morphology, and the results from this have not been congruent with the more recent molecular phylogenetic analyses. The subfamilial and tribal classification for the family is currently in a state of flux, with many of the groups being found to be grossly paraphyletic or polyphyletic.

Genera

According to the Angiosperm Phylogeny Website as of 2014, 434 genera are in the family Apiaceae.

Ecology

The black swallowtail butterfly, Papilio polyxenes, uses the family Apiaceae for food and host plants for oviposition. The 22-spot ladybird is also commonly found eating mildew on these shrubs.

Uses

Many members of this family are cultivated for various purposes. Parsnip, carrot and Hamburg parsley produce tap roots that are large enough to be useful as food. Many species produce essential oils in their leaves or fruits and as a result are flavourful aromatic herbs. Examples are parsley, coriander, culantro, and dill. The seeds may be used in cuisine, as with coriander, fennel, cumin, and caraway.
Other notable cultivated Apiaceae include chervil, angelica, celery, arracacha, sea holly, asafoetida, galbanum, cicely, anise, lovage, and hacquetia.

Cultivation

Generally, all members of this family are best cultivated in the cool-season garden; indeed, they may not grow at all if the soils are too warm. Almost every widely cultivated plant of this group is a considered useful as a companion plant. One reason is because the tiny flowers clustered into umbels, are well suited for ladybugs, parasitic wasps, and predatory flies, which actually drink nectar when not reproducing. They then prey upon insect pests on nearby plants. Some of the members of this family considered "herbs" produce scents that are believed to...mask the odours of nearby plants, thus making them harder for insect pests to find.

Other uses

The poisonous members of the Apiaceae have been used for a variety of purposes globally. The poisonous Oenanthe crocata has been used to stupefy fish, Cicuta douglasii has been used as an aid in suicides, and arrow poisons have been made from various other family species.
Daucus carota has been used as coloring for butter.
Dorema ammoniacum, Ferula galbaniflua, and Ferula sumbul are sources of incense.
The woody Azorella compacta Phil. has been used in South America for fuel.

Toxicity

Many species in the family Apiaceae produce phototoxic substances that sensitize human skin to sunlight. Contact with plant parts that contain furanocoumarins, followed by exposure to sunlight, may cause phytophotodermatitis, a serious skin inflammation. Of all the plant species that have been reported to induce phytophotodermatitis, approximately half belong to the family Apiaceae.
Phototoxic species include Ammi majus, the parsnip and numerous species of the genus Heracleum, especially the giant hogweed. The family Apiaceae also includes a smaller number of poisonous species, including poison hemlock, water hemlock, and fool's parsley.
Some members of the family Apiaceae, including carrot, celery, fennel, parsley and parsnip, contain polyynes, an unusual class of organic compounds that exhibit cytotoxic effects.