WEEDS OF PONDS, RIVERS, DITCHES 325 



composed of long, thin, branch-like segments which are 

 weak and collapse into the form of a paint brush when 

 lifted out of the water. 



R. peltatus Fries, resembles this, but the segments of 

 the submerged leaves are more rigid, and do not close 

 up when they are taken from the water (Fig. 91). 



R. trichophyllus Chaix., found chiefly in stagnant water, 

 has black, rigid, submerged leaves, with short flower 

 stalks and few or no floating leaves. 



R. fluitans Lamk. has long peduncles to the flowers ; 

 leaves like the preceding. The plant is found usually 

 in running water. 



Lesser Spearwort (R. Flammula L.). See pp. 15 5, 279. 



Greater Spearwort (R. Lingua L.) is a somewhat rare 

 species, with flowers like a large yellow buttercup, ij 

 to 2 inches in diameter ; it is found in marshes and 

 ditches. The leaves are long and undivided, lanceolate, 

 with their base partly clasping the hollow, smooth stem. 



Celery-leaved Crowfoot (R. sceleratus L.). See pp. 



Marsh Marigold (Caltha palustris L.) is a well-known 

 inhabitant of marshy places and ditches. The leaves 

 are roundish or kidney-shaped, and the flowers golden- 

 yellow, i to 2 inches in diameter. 



Yellow Water-lily (Nuphar luteum L.) is common in 

 lakes and ditches which are from 6 to 12 or 15 feet 

 deep. It possesses a strong creeping rootstock, which 

 is buried in the mud below. The leaves are leathery, 

 circular, and deeply divided at the base ; some of them 

 are submerged, others float on the surface of the 

 water. The yellow flowers, over 2 inches across, have 

 eighteen to twenty petals, and smell like brandy. The 



