362 MONffiCIA POLYANDRIA. [CL. XXI. 



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'RIA. ARROW-HEAD. 



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

 nent 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. 436. 



1. S. sagittijolia. 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. ARCM. 



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. Co- 

 rolla 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 distance 

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

 globular, juicy, one-celled. Seeds several, roundish. Name of 

 doubtful origin. 437. 



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

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

 tuse. - 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. 



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 5 anthers roundish, two-lobed. 



