SHINGLE PLANTS
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of humus contained in the bank. The plants of shingle beaches fall under two categories. There are those which germinate and establish directly upon the bank, and those, on the other hand, that occur on the ground over which the shingle drifts, and which rise up through the shingle and colonize it. The characteristic plants of shingle include the Sea Dock (Rumex trigranulaius), Horned Poppy (Glaucium luteum), Yellow Stone-crop (Sedum acre), Sea Campion (Silene maritima), the Sea Pea {Lathyrus maritimus), grasses such as Triticum junceum, Festuca rubra, and Poa annua, and the shrubby Sea Blite (Suceda fruti-cosa). This last-named as a stabilizer is most important, and its relation to shingle will be fully considered in Chapter VII. It occurs wild in this country on the Chesil Bank and on the coasts of Essex and Norfolk, and in Poole Harbour.