ALISMACEi^. 69 



bulbs at their extremity, and from which new plants are developed. 

 Early leaves all submerged or floating on the surface of the water, 

 resembling the floating leaves of Sparganium simplex, but broader 

 towards the apex, and ha%ang several ribs with lax areolation between 

 them ; later leaves rising out of the water, triangular, with 2 long acute 

 basal lobes pointing backwards, commonly nearly as long as the rest of 

 the lamina, which as well as the basal lobes has several ribs connected by 

 cross veins. Scape at length rather longer than the leaves, with distant 

 wliorls with membranous bracts at the base ; 1 or 2 of the lowest 

 whorls consist of female flowers on peduncles rarely more than \ inch 

 long even in fruit ; the two or three uppermost whorls of male flowers 

 on peduncles ^ to 1;^ inch long while the flowers are expanded. Flowers 

 3 (or 4) in a whorl. Female flowers about ^ inch across, the male ^ 

 inch, both with the inner perianth leaves diaphanous, pure white with 

 a purple base, deciduous. Anthers dark purple. Fruit in heads ^ to -| 

 inch in diameter, half-obovate-semicircular, flattened, thin, olive, with 

 an apiculus forming a continuation of the upper margin, the greater 

 portion consisting of a corky wing; seed-bearing portion oblong. 

 Plant bright green, glabrous, very variable in the shape and size of 

 the leaves and height of the scapes according to the depth of the 

 water in which it grows ; the former 2 inches to 1 foot long, including 

 the basal lobes, the latter 4 inches to 2 feet 6 inches. 



Common Arrowhead. 



French, Sagittaire fleche d'eau. German, Gemeines Pfeilkraxit. 



Tills is a plant of remarkable beanty, and affords the finest example in nature of 

 the arrowheaded leaf. Its roots contain an amylaceous matter, -which is said to form 

 a nutritions food, and is eaten by the Chinese and Kalmnk Tartars. 



GENUS IV.— Ps.'Ll^'M.K. Linn. 



Flowers perfect. Perianth with the 3 outer leaves herbaceous, sub- 

 persistent ; 3 inner leaves larger, petaloid, caducuous. Stamens 6, 

 hypogynous ; filaments filiform ; anthers introrse, affixed by the back. 

 Ovaries very numerous, free, 1 -celled and 1-ovuled ; stigma simple. 

 Fruit of numerous verticillate or subcapitate achenes. 



Marsh herbs with a cormose rhizome and radical stalked leaves with 

 cancellate venation, rounded, cordate or wedgeshaped at the base, 

 sometimes with the lamina absent : occasionally the scapes root and 

 produce leaves at the nodes. Flowers white or pale hlac, in a panicle 

 on a scape with verticillate branches or pedicels. 



The derivation of the name of this plant is said to be from tho Celtic alis, water, 

 where the species grow. 



