362 MONCECIA POLYANDRIA. [cL. XXI. 



rising above the water : petals small, white. Perennial : flowers in 

 July : grows in ditches and ponds, in England and Wales : not 

 common. Eng. Bot. vol. iv. pi. 218. Eng. Fl. vol. iv. p. 143. 1361. 



17. SAGITTA'KIA. ARROW -HEAD. 



Barren Flowers numerous. Calyx of three egg-shaped, per- 

 manent leaves. Corolla of three roundish, spreading, deciduous 

 petals, thrice the size of the calyx. Filaments numerous, about 

 twenty-four, awl-shaped, collected into a round head ; anthers 

 heart-shaped, much shorter than the petals. 



Fertile Flowers fewer, below the others. Calyx and corolla 

 as above. Germens numerous, collected into a head, compressed, 

 bulging externally, tapering into very short styles. Stigmas 

 acute, permanent. Seeds numerous, inversely egg-shaped, 

 compressed, margined. Named from sagitta, an arrow r . 436. 



1. S. sagittifblia. Common Arrow-head. Leaves arrow-shaped, 



acute. Leaves all from the root, on long cellular stalks : flowers 



white, three in a whorl. Perennial : flowers in July : grows in 

 ditches and at the edges of pools and rivers, in England and Ireland : 

 frequent. Eng. Bot. vol. ii. pi. 84. Eng. Fl. vol. iv. p. 144. 1362. 



18. A'RUM. ARUM. 



Common calyx of one erect, sheathing, oblong leaf, convolute 

 at the base, converging at the top, compressed in the middle, 

 coloured within, containing the flowers arranged upon a common 

 stalk, the latter terminating in a coloured, naked appendage. 

 Corolla none. 



Barren Flowers. Filaments numerous, very short, arranged 

 in several close rows round the stalk, within the convoluted 

 part of the calyx, surmounted at a little distance above by a 

 ring of pointed, antherless filaments ; anthers two-lobed. 



Fertile Flowers. Germens sessile, inversely egg-shaped, in 

 a dense ring round the lower part of the stalk, at a small dis- 

 tance below the barren flowers. Styles none ; stigma downy. 

 Berry globular, juicy, one-celled. Seeds several, roundish. 

 Name of doubtful origin. 437. 



1. A.maculdtum. Cuckow-pint. Wake Robin. Stem none ; leaves 

 halberd-shaped, entire; common-stalk of the flowers club-shaped, 



obtuse. Root tuberous : leaves stalked, spotted with black : 



berries scarlet. The root, when dried, affords a nutritious flour, 

 fit for making bread. Perennial : flowers in May : grows in bushy 

 places, hedges, and the borders of fields. Eng. Bot. vol. xix. pi. 

 1298. Eng. Fl. vol. iv. p. 146. 1363. 



19. POTE'RIUM. SALAD-BURNET. 



Barren Flowers. Calyx of three egg-shaped, spreading, co- 

 loured, deciduous leaves. Corolla of one petal, tubular, deeply 

 divided into four egg-shaped, spreading, permanent segments. 

 Filaments numerous, from thirty to fifty, hair-like, much longer 

 than the corolla ; anthers roundish, two-lobed. 



