Alismacee—Sagittaria. 465 
1. S. sagittifolia (fig. 225). Arrow-head.—This is the only 
one that need occupy our attention. It isa common plant in 
the South of England, about a foot high, with ephemeral uni- 
Fig. 225, Sagittaria sagittifolia, (4 nat, size.) 
sexual flowers an inch or more in diameter, white with a purple 
centre. Segments of the perianth all similar; stamens nume- 
rous. It blooms throughout the Summer. 
2. BUTOMUS. 
This is a genus comprising one or two very elegant aquatic 
plants with slender erect triquetrous leaves and a tall scape 
surmounted by a large umbel of rosy-pink flowers. Perianth- 
segments free, equal, all coloured. Stamens 9. Carpels about 
6, many-seeded. The derivation of the generic name is ob- 
scure. 
1. B.umbellatus. Flowering Rush.—One of our handsomest 
native aquatics and the only British plant having 9 stamens. 
It grows from 3 to 6 feet high according to conditions, and 
flowers at Midsummer. 
Aponogeton distéchyus is a handsome aquatic plant, re- 
markable fer its floating branched spikes of small fragrant 
bracteate white flowers. Leaves oblong-lanceolate, on long 
petioles, floating. This plant is a native of the Cape of Good 
Hope, but it will flourish in a lake or stream if planted at a 
II It 
