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.
No seeds of this plant have been detected in Glacial beds. It is a plant of the Warm Temperate Zone, common to Europe, N. Africa, and Western Asia. It has been introduced in the United States. It is absent from Merioneth and Flint in N. Wales, and occurs in N. Lines only in the Trent province, and in the Humber province only in S.E. and N.E. Yorks. It is not found in the Isle of Man. In the E. Lowlands it only occurs in Berwick, Haddington, Linlithgow; in the E. Highlands only in Fife and Kincardine. It occurs also in Argyll, Dumbarton, Clyde Isles, and the Shetlands, and elsewhere on the maritime coasts except in the counties named. It is found in Ireland and the Channel Isles.
The Yellow Horned Poppy takes the place on the sea-coast of the Red Poppies inland. It is a halophyte, addicted to salt, and occurs around the whole of the British coast except in the above counties. It grows on rocky coasts as well as in the flat eastern counties, forming beautiful clumps usually on sandy soil.
It is a very free-flowering plant, whose golden-yellow blooms form a pleasing contrast to the widespreading leaves of a bluish-white colour. The crisped wavy leaves, nearly clasping, conceal the robust, tall, branched stems, and give the plant a cabbage-like habit; the stem is smooth, the leaves stiffly hairy.
The long capsules or pods, 6-9 in. long, warted and rough, are curved, the seeds brown, with ridges enclosing squarish areas, and the lobes of the stigma (3) are spreading. The large, yellow, poppy-like flowers are 2-4 in. across and distinctly characterize the plant. They last two days.
The stem is 2-4 ft. high. Flowers last from June to October, and the plant is annual or biennial.
When pollinated by its own pollen the Yellow Horned Poppy bears seed. The flowers are conspicuous and suited to insect visits, the stigma being deeply lobed and serving for an alighting place.
The Yellow Horned Poppy is dispersed by its own agency. The pods are long and narrow, and the seeds are dispersed by the tension and splitting open of the pods when dry. The seeds are numerous.
The Yellow Horned Poppy is a halophyte, and requires a saline soil, such as that afforded by a maritime habitat.
Glaucium was the name given by Tournefort, from the Greek glaucos, alluding to the bluish-green colour of the leaves, and flavum alludes to the yellow flowers.
The English names are Horned Poppy, Sea Poppy, Spatmore, Squatmore. It is called Squatmore, or Bruisewort, because it was once employed in curing bruises. In the language of the western counties squat equals bruise, and a root is called a more.
This plant was regarded as a herba mirabilis in ancient times, being called Ficus infernalis. It was one of the plants used by witches in their potions. In the witches' song Ben Jonson says:
"Yes, I have brought to help our vows, Horned poppy, cypress boughs, The fig tree wild that grows on tombs, And juice that from the larch tree comes".