WATER FENNEL 69 



Water Fennel (Ranunculus trichophyllus, Chaix.) 



Seeds of Batrachian Ranunculi, w hich come under tlic old aop-reo-ate 

 Ranunculus aqiiatilis, ha\e been found in some deposits, such as Pre- 

 glacial. Early Glacial, Interqlacial, Lale Glacial, and Neolithic beds. 

 To-day the distribution ot this ayqrec^ate extends o\er Europe, West 

 Asia, the Himalayas, N. America, or the Warm Temperate Zone. 

 In occurrence it is absent from Cornwall in the Peninsula, South Hants 

 and E. Sussex in the Channel province, but occurs throughout the 

 Thames province; in Anglia it is absent from Northampton, but present 

 in the whole of the Severn province, and absent from Notts in the 

 Trent province, occurring in Carnarvon and Denbigh onlv in Wales, 

 in S.W. and N.E. Yorks, Tyne province, and in Scotland in Dum- 

 fries, Kirkcudbright, Haddington, Edinburgh, Fife, Stirling, Perth, 

 Forfar, Clyde Islands, Sutherland, and the Hebrides. It is also found 

 in Ireland. 



In all the Water Buttercups the leaves are much divided. There 

 are two types. Those that tloat are rounded with 3-6 wedge-shaped 

 lobes, which are in\-ersely egg-shaped or rounded. The submerged 

 leaves, on the other hand, are linear, much divided, with numerous fine 

 segments. There are other modifications of this type, some, as R. 

 fluilans, having no floating leaves, but very long hair-like leaves (sub- 

 merged) only when growing in quickly-flowing water. At the other 

 extreme are plants, as R. hcderaccus, with few if any submerged or 

 thread-like leaves, and only the rounded floating types of leaf. The 

 types with two kinds of lea\es may become stranded on land and then 

 adapt them.selves to such conditions, though as a rule the submerged- 

 leaf type cannot succeed on land or the floating leaf under water. 



This .species is an aquatic like other Batrachian Ranunculi, with 

 thread-like submerged leaves, hydrophilous, preferring the still water 

 of a pond or lake to that of running water, thus differing from Ramtn- 

 culus penicillatus. It forms clusters and groups growing in the centre 

 of the pond, and is associated with Water Cress, Water Persicaria, 

 Pondweeds, Duckweed, Water Plantain, and the semi-sul)merged 

 Celery-leaved Water Crowfoot. 



Water Fennel is adapted, like all aquatic plants, to growth in water, 

 with linear leaves and .slender stems which float readily in the water. 



Water I-'ennel is distinguished fi-om other Water Buttercups h\ its 

 small flowers, its rigid leaves which do nnt collapse when removed 

 from the water, and the short compact flower-stalk. 



