This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The distribution of Sea Holly to-day (as far as our knowledge goes) is limited to the North Temperate Zone in Europe, and N. Africa. In Great Britain it is absent from West Sussex, Northumberland, Wigtown, Berwick, as far as Aberdeen, and N. Ebudes, occurring on the coasts of other maritime counties, and to the north it is found in the Orkneys and Hebrides. It is found throughout Ireland.
A maritime species, addicted to a sandy habitat, on the shores of the British Isles, it is both a xerophyte or dry-soil type and a halophyte or salt-lover. It grows with Sea Kale, Sea Rocket, Samphire, Thrift, Sea Milkwort, and many other sand-loving species.
Photo. J. H. Crabtree - Sea Holly (Eryngium maritimum, L.)
The English name suggests one of its main characteristics, its spinous character, like that of Holly, and its Thistle-like appearance. The plant is bluish-green in colour, and has stiffly hairy, spiny, leathery leaves, the radical leaves being rounded and 3-lobed, with cartilaginous margins, and folded. The stem is rigid, much-branched, with numerous leaves, the upper leaves clasping the stem and the lobes starting from a common centre. The plant has long thick roots.
The flowerheads, which are blue, are in heads with involucres, with a whorl of stiff coloured bracts or leaflike organs below, spinous, longer than the heads. The scales in the receptacle are 3-toothed. The petals are narrow and deeply notched, turned down, and help with the anther-stalks to close the flower, though they can be pushed on one side by an insect.
Eighteen inches or two feet is the usual height of the Sea Holly. To find the flowers search the seaboard in July and August. Perennial, and increased by roots, the plant is well established in its habitats.
The flowers are small and inconspicuous, and not adapted for insect visits, like some other maritime species. The styles are threadlike and erect, and the petals are narrow and have the point turned in, whilst the umbels are in very dense heads, and are more liable in this way to be self- than cross-pollinated. The anthers ripen first. The honey is secreted by a disk with 10 rays at the base, and is concealed.
The achenes are flattened, and when ripe are aided in dispersal by the wind or passing herds, being detached and jerked to a distance.
Sea Holly is a salt-lover, and delights in a saline soil, and is also a sand plant, addicted to a sand soil.
The Lepidoptera Silky Wainscot, Argyrolepia maritima, Conchylis francillana and the Dingy Skipper Thanaos (Hesperia) tages, and a Heteropterous insect, Therapha Hyoscyami, feed on it.
Eryngium, Dioscorides, is latinized from the Greek name of the plant, and the second name (Latin) indicates its habitat.
Sea Holly is called Eringo, Eryngo, Sea Holly, Sea Holme, Sea Hulver, Ringo-roots.
The plant used to be employed as a love charm, and it was candied and sold in Shakespeare's day as the "kissing comfits" of Falstaff. In Sweden the tops are all eaten like asparagus. It is held by the Arabs to be a restorative, the chief virtue residing in the roots.
Essential Specific Characters: 122. Eryngium maritimum, L. - Root fleshy, large, stem rigid, glaucous, leaves spinous, clasping, leathery, palmate, involucral leaves 3-lobed, flowers blue, in a dense head, with a whorl of bracts.