496 THE ALISMA TAMILT. 



long, sagittate ; the lobes of the base nearly as long as the terminal one, all 

 pointed, but varying much in width. Flower-stem leafless, erect, longer 

 than the leaves, bearing in its upper part several distant whorls of rather 

 large, white flowers ; the 3 inner segments of the perianth twice as long as 

 the 3 outer green ones ; the upper flowers usually males, on pedicels J to 1 

 inch long ; the lower ones females, on shorter pedicels. 



In watery ditches, and shallow ponds and streams, dispersed over the 

 greater part of Europe and central and Russian Asia to the Arctic regions. 

 Represented in North America by a slight variety now said to be a distinct 

 species. In Britain, limited to England and Ireland, with the exception of 

 a single station near Paisley, in Scotland. Fl. summer and autumn. 



Til. ALISiaA. ALISMA. 



Aquatic herbs, erect or rarely floating with radical, long-stalked leaves ; 

 the flowers either in a terminal umbel, witli or without whorls of pedici'llate 

 flowers below it, or in a panicle with whorled branches each bearing a 

 similar nmbel. Perianth of 3 outer, small, herbaceous segments, and 3 

 much larger inner ones, petal-like, and very dehcate. Stamens 6. Carpels 

 numerous, small, and 1-seeded, either arranged in a ring round the axis, or 

 irregularly in a globular head. 



A genus now known to comprise a considerable number of species, chiefly 

 American, but some of them widely distributed over nearly the whole 

 world. 



Flowers numerous, in a loose panicle. Carpels forming a ring round 



the axis of the flower 1. Common A. 



Flowers few, in a single imibel. Carpels irregularly arranged in a glo- 

 bular head. 

 Stems erect or creeping. Carpels with 4 or 5 prominent ribs ... 2. Leaser A. 

 Stems floating. Carpels with 12 to 15 slender ribs 3. Floating A. 



1. Common Alisma. Alisma Flantago, Linn. 

 (Eng. Bot. t. 837. TFater Flantain.) 



Rootstock perennial, becoming almost bulbous by the thickened sheath- 

 ing bases of the leafstalks. Leaves radical, varying from ovate to narrow- 

 lanceolate. Flower-stem 1 to 3 feet high, with whorled branches, unequal in 

 length, forming a loose, pyramidal panicle. Flowers rather small, of a pale 

 rose-colour, on long whorled pedicels. Fruit of 20 to 30 carpels, arranged 

 in a single ring round a broad, flat, central axis. 



In watery ditches, ponds, and edges of streams ; common in Europe and 

 central and Russian Asia, and North America, extending to the Arctic re- 

 gions, and reappearing in Australia. Abundant in Britain, excepting the 

 north of Scotland. Fl. all summer. 



2. Iiesser Alisma. Alisma ranunculoides, Linn. 

 (Eng. Bot. t. 326.) 

 The leaves and peduncles form annual tufts, but will occasionally emit 

 runners for a succeeding year. Leaves narrow-lanceolate, or sometimes re- 

 duced to a linear leafstalk. Flower-stems, in the ordinary state, simple, 

 with a single terminal umbel, or rarely a second whorl below it. Flowers 

 larger than in the comOTOK ^., sometimes near an inch diameter. Carpels 

 irregularly arranged in a globular head in the centre of the flower. 



