APOCARPEiE 373 



It is only naturalised in Scotland. In Ireland it is 

 quite local. 



Ponds, meres, streams, canals, ditches, form the 

 habitat of Arrow-head, usually clear shallow water. 

 It is found in the fresh-water aquatic formation in 

 waters relatively rich in mineral salts, in nearly 

 stagnant waters in the floating-leaf association. 



The stem is swollen below and produces stolons, 

 the rootstock being creeping, with bulbous tubers, 

 which are rounded in winter. There are early sub- 

 merged current leaves, or leaf-stalks of the ribbon 

 type, linear, membranous. The leaves are radical, 

 and later rise above the water. At first, as in Arum, 

 they are not arrow-shaped, but oblong or nearly 

 heart-shaped below. The ultimate type has the 

 basal, spreading, lance-shaped, straight lobes nearly 

 as long as the terminal lobe, long-pointed. The 

 leaf-stalk is three-sided, and long and stout. 



The flowers are white, large, with a purple spot at 

 the base, borne on a long, leafless scape, longer than 

 the leaves, in three to five distant whorls, with three 

 to five flowers in each. The bracts are short, blunt, 

 membranous. The three inner perianth-segments 

 are twice as long as the outer green ones. The plant is 

 monoecious. The lower whorls of flowers are female, 

 on short ultimate stalks ; the upper long-stalked 

 ones are male, and are larger flowers. The petals 

 fall at length. The anthers are purple. The ripe 

 carpels are numerous, and flattened at the margin, 

 obliquely inversely ovate, with a short point, with 



