54 BRITISH FLOWERING PLANTS chap. 



Batraehium. Like most other water plants they are 

 glabrous, while the land species are generally hairy. 

 The forms are very variable, and some botanists make 

 numerous species, which Bentham and Hooker reduce to 

 two — R. aquatilis, in which the lower leaves are finely 

 cut up, and the receptacle is usually hairy ; and 

 R. hederaceus, in which all the leaves are rounded with 

 broad lobes, and the receptacle is glabrous. 



R. aquatilis. — The most interesting feature is the 

 possession of the two kinds of leaA'^es (Fig. 30). Those 

 which float on the surface are rounded in outline and 

 cut more or less into three or six wedge-shaped, obovate 

 or rounded lobes ; while the submerged leaves are 

 divided into numerous fine linear segments. It is a 

 very variable species, and has great power of adapting 

 itself to difierent conditions, such as the depth of the 

 water or the rapidity of the stream. It will also grow on 

 land, in which case, however, the habit is very different. 

 The leaves are so far adapted to their surroundings that 

 the submerged ones cannot live out of, nor the floating 

 ones under, water. The size of the flower varies consider- 

 ably. The petals are 5 or sometimes more in number, the 

 stamens from 8 to 20. It has a slight scent, and secretes 

 honey in a nectary at the base of each petal ; the honey- 

 gland is not protected by a scale. The yellowish base 

 of the petal serves to guide insects towards the honey. 

 It grows and flowers freely, sometimes quite covering 

 small pieces of water. It is visited by many small 

 flying insects, especially flies. If the water is high the 

 flowers remain submerged and closed and fertilise them- 

 selves. The plant extends to all temperate regions. 



R. hederaceus is smaller, and does not produce the 

 finely divided, submerged leaves. It secretes very little 

 honey, and is not much visited by insects. This species 

 is common in Western and Northern Europe. 



Our other species of Eanunculus are yellow. 



R. sceleratus, so called from its bitter acrid juice, 

 which raises blisters on the fiesh, and from the time of 

 the Herbalists is referred to as thus used by beggars to 



