the calyx striped green and white, together with the white base 
of the calyx, and the peculiar contraction there, are characteristic 
of the present species. 
Dzxsor. An aquatic plant, with the /eaves on long terete petioles, 
floating, orbicular-ovate, peltate, strongly but irregularly toothed, 
dark green, glabrous and smooth above, equally glabrous beneath, 
paler and with singularly prominent veins especially at their bases ; 
these veins radiating, dichotomous, particularly so towards the 
margins, and united by slender transverse and often branched 
and reticulated veinlets. Flowers rising above the water, on 
terete peduncles. The bud elliptical. Calyx of four elliptical 
obtuse sepals, veined and striated green and white; the base 
singularly depressed and white. Pefa/s numerous, white. Sta- 
mens and stigmas yellow. 
