28 ENGLISH BOTANY. 



not enlarged upwards. Sepuls with their lamina rhombic-roundish, 

 Fruiting-spike cylindrical, many-flowered, dense. Fruit reddish, small, 

 rouudish-obovate, slightly compressed, convex on the upper margin, 

 semicircular and slightly keeled on the back, with a short terminal 

 beak. Leaves dull olive-green, often tinged with reddish-brown. 



Var. a, genuinus. 



Plate MCCCC. 



Lowest leaves narrower and thinner in texture than the upper ones, 

 which arc rounded or subcordate at the base. 



Var. 0, pseudo-fluitans. 



Lower leaves membranous, elliptical-strapshaped, attenuated at 

 each end; floating leaves subcoriaceous, gradually attenuated into 

 the petiole. 



Var. 7, ericetorum. 



Leaves all similar, subcoriaceous, floating or rising out of the water, 

 longly-stalked, with an oval or oblong-oval or roundish lamina. 



Var. a in shallow water. Var. 3 in deep water, Dunsappie Loch, 

 Edinburgh; Buttermere (Professor Oliver). Var. y in wet places, 

 chiefly on heaths, where it is extremely abundant, and genei-ally dis- 

 tributed. The distribution of vars. a and /3 1 am unable to give. 



England, Scotland, L-eland. Perennial. Summer, Autumn. 



A veiy variable plant, with the stems rarely above a span long, as 

 deep-water forms appear to be rare. The leaves are very variable 

 in shape, and in many cases can only be distinguished from those of 

 P. natans by being less coriaceous and not having the substance of the 

 leaf continued for some distance down the petiole ; the lamina, how- 

 ever, is generally smaller, commonly about 1^ inch long, and there 

 are no grasslike petioles destitute of lamina, which are the only sub- 

 merged leaves present in P. natans at the time of flowering. The 

 lower leaves have a broad lamina, like the others, only usually more 

 attenuated at the base, and of more membranous texture. The 

 (Stipules are large, as in P. natans, but much less persistent, as the 

 iibres which form their ribs are less tough. The peduncles are much 

 more slender, the spike shorter, rarely above 1 inch long. The fruit 

 is only about ^V or ^V i"*^^ ^^"ni ^"'i reddish when ripe. 



Var. 3 very closely resembles the true P. fluitans, having long 

 narrow pellucid submerged leaves, attenuated at each end, and the 

 floating leaves are narrowed at the base. The shape of the sepals, 

 hoAvever, is rounder than in the true P. fluitans, which has the fruit the 

 size of P. natans. 



