232 PROCEEDINGS COTTESWOLD CLUB 1914 



for watercress. There is at some stages a certain resemblance 

 in foliage between the two plants, but none, I should think, 

 in the taste. Syme says that both are harmless. 



The points in H. nodifiormn which will form the basis 

 of my remarks here, are two : — ist, the variety of its habitats, 

 2nd, the extreme variability of its forms. 



Habitat. — It is always a plant of watery places, though 

 its foliage and inflorescence are almost always raised above 

 the surface of the water. Its favourite spot is some deepish 

 rather shaded ditch, which normally has several inches to a 

 foot of water ; but almost any fresh-watery spot will do ; 

 rough, swampy ground, either shaded or occupied by a good 

 deal of varied low-growing vegetation ; muddy margins of 

 ponds ; parts of grassy or heathy hillsides which are wet in 

 winter and dry in summer ; the damper parts of the flat 

 sandy ground which usually backs sand dunes, and which 

 completely dries up in an ordinary summer, however damp 

 it may be in winter. Its roots are probably always within 

 easy reach of water, even if the surface of the ground is dry. 



The forms of this species are numerous and puzzling. 

 In 1906 Mr E. G. Baker and I wrote a paper on those which 

 occur in Great Britain, confining ourselves to those which 

 have been actually described and named as varieties. There 

 is the large common ditch-form, named var. vulgare F. Schultz, 

 running to a yard or more in height, robust, with large pin- 

 nate leaves, largest where they spring in tufts from the root, 

 and with nearly sessile umbels of many rays ; the fruit is 

 longer than broad, and very dark brown, almost black, in 

 colour. Next comes var. ochreatum of de CandoUe, which has 

 a stem rooting more freely at the joints, rather narrower leaf- 

 lets, and rather longer stalks to the umbels ; it is a smaller 

 and slenderer plant. Var. pseiido-repens of H. C. Watson is 

 a very small slender plant, which roots freely at the nodes, 

 has longer-stalked umbels, and few small roundish bluntly- 

 toothed leaflets. Var. longipedunculatum F. Schultz is a long 

 slender weak plant, rooting a good deal at the nodes, and 

 having unusually long internodes. More will be said of this 

 variety later on. (See Journal of Botany, 1906, p. 185.) 



