Hogweed (Heracleum sphondylium sibiricum)
Description
Heracleum sphondylium reaches on average 50–120 centimetres (20–47 in) of height, with a maximum of 2 metres (6 ft 7 in). From large reddish rhizomatous roots rises a striated, ridged, hollow stem with bristly hairs. The leaves can reach 50 centimetres (20 in) of length. They are pinnate, hairy and serrated, divided into 3–5 lobed segments. This plant has pinkish or white flowers with 5 petals. They are arranged in large umbels of up to 20 cm of diameter with 15 to 30 rays. The peripheral flowers have a radial symmetry. Flowering typically occurs between June and October.The terminal umbels are flat-topped and the outermost petals are enlarged. The flowers are pollinated by insects, such as beetles, wasps and especially flies. The small fruits are flattened and winged, elliptical to rounded and glabrous, up to 1 cm long. The seed dispersal is by wind (anemochory). The characteristic pig-like smell of the flowers gives it its name.H. sphondylium is smaller than dangerous Heracleum mantegazzianum (giant hogweed) and Heracleum sosnowskyi (Sosnowsky's hogweed), and should not be confused. However, it contains some of the same phytophototoxic compounds (furanocoumarins), albeit at lower concentrations, and there is evidence that the sap from common hogweed can also produce phytophotodermatitis (burns and rashes) when contaminated skin is exposed to sunlight. Care therefore needs to be used when cutting or trimming it, to prevent 'strimmers rash'. The small picture-winged fly Euleia heraclei is, as its name suggests, found on hogweed.
Taxonomic tree
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Domain: Eukarya
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Kingdom: Plantae
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Phylum:
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Class: Magnoliopsida
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Order: Apiales
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Family: Apiaceae
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Genus: Heracleum
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