Umbel

An umbel is an inflorescence which consists of a number of short flower stalks (called pedicels) which spread from a common point, somewhat like umbrella ribs. The word was coined in botany in the 1590s, from Latin umbella "parasol, sunshade."^[1] The arrangement can vary from being flat topped to almost spherical. Umbels can be simple or compound. The secondary umbels of compound umbels are known as umbellules or umbellets.^[2] A small umbel is called an umbellule.^[2] The arrangement of the inflorescence in umbels is referred to as umbellate, or occasionally subumbellate (almost umbellate).

Umbels are a characteristic of plants such as carrot, parsley, dill, and fennel in the family Apiaceae; ivy, aralia and fatsia in the family Araliaceae; and onion (Allium) in the family Alliaceae.

An umbel is a type of indeterminate inflorescence.^[2][3] A compressed cyme, which is a determinate inflorescence, is called umbelliform if it resembles an umbel.

Gallery

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  Compound umbel of a hemlock-parsley, Conioselinum pacificum (Apiaceae)

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  Compound umbel of a wild carrot, Daucus carota (Apiaceae)

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  Simple umbel of Fatsia japonica (Araliaceae)

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  Involucrate simple umbels of Primula veris.

References

1. umbel etymology
2. Beentje, H.; Williamson, J. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.
3. Walters, D.R.; Keil, D.J. (1975). Vascular Plant Taxonomy. Dubuque: Kendall/Hunt Publishing Company.

Further reading

• Hinderer, Walter; Noé, Wolfgang; Seitz, Hanns Ulrich (1983). "Differentiation of metabolic pathways in the umbel of Daucus carota". Phytochemistry 22 (11): 2417–2420. doi:10.1016/0031-9422(83)80131-9. ISSN 0031-9422.
• Toben, H.-M.; Rudoph, K (1996). "Pseudomonas syringae pv. coriandricola, Incitant of Bacterial Umbel Blight and Seed Decay of Coriander (Coriandrum sativum L.) in Germany". Journal of Phytopathology 144 (4): 169–178. doi:10.1111/j.1439-0434.1996.tb01510.x. ISSN 0931-1785.
• Peterson, L. E.; Clark, R. J.; Menary, R. C. (1993). "Umbel Initiation and Stem Elongation in Fennel(Foeniculum vulgare)Initiated by Photoperiod". Journal of Essential Oil Research 5 (1): 37–43. doi:10.1080/10412905.1993.9698168. ISSN 1041-2905.