Eryngium maritimum, the sea holly or sea eryngo, or sea eryngium, is a perennial species of flowering plant in the family Apiaceae and native to most European coastlines. It resembles a plume thistle in appearance on account of its burr-shaped flower. Despite its common name, it is not related to true holly, but is an umbellifer. Etymology E. maritimum was formally described by Linnaeus in his Species Plantarum I: 233 (1753). The generic name Eryngium derives from Greek and may have developed from a description of the plant by Theophrastus (300 BC), who referred to it as “Eryngion”, meaning a spiny plant. Alternatively, the name may have derived from the Greek word “eruggarein”, meaning to eructate (belch), since the plant was used to treat various disorders such as trapped gases. The specific epithet maritimum means “of the sea”. The common English name appears to date from the 16th century. In his 1548 publication The Names of Herbes, the naturalist William Turner stated that “Eryngium is named in englishe sea Hulver or sea Holly”. Taxonomy Although hybrids of E. maritimum have been reported, they are relatively few. For example, records have been made of a hybrid between E. maritimum and E. campestre (=Eryngium 9 rocheri Corb. ex Guétrot) in France, and in the region of Valencia, Spain. The species’ chromosome number is 2n = 16 Description Sea holly is a glabrous, intensely glaucous, clump-forming perennial growing to around 60 cm tall. It is also a slightly succulent xerophyte with a deep well-developed root system and waxy leaf cuticles. The leaves are stiff, spiny, and leathery. The basal leaves, which measure 5 – 15 cm long and are rolled when young, are palmately 3-lobed and suborbicular, truncate, or cordate at the base. The stem leaves are similar, but are smaller, sessile, and palmate. All leaves have thick cartilaginous margins, with often purplish veins and stomata on both sides. The petiole is channeled and dilated at the base. The cotyledons are abruptly contracted into a petiole. The flowers are bluish white and measure 8mm across, in 1.5 – 2.5 cm heads The bracts are spiny, and the bracteoles are longer than the flowers. The sepals measure 4 – 5 mm and are longer than the petals. The fruit is 13 – 15 mm, more or less uncompressed and covered in stigmatic papillae which become longer towards the apex. The styles are about 6