130568 RIGID HORNWORT Ceratophyllum demersum (Ceratophyllaceae) Aquatic. Submerged perennial with rather brittle stems; by late summer these acquire a coating of chalk and silt (as do the leaves to a lesser extent). FLOWERS are minute and borne at leaf nodes (Jul-Sep). FRUITS are warty and beaked, with 2 basal spines. LEAVES are rigid, toothed and fork 2-3 times; in whorls. STATUS-Locally common only in England.