ON SOME FORMS OF RANUNCULUS FLAM AWL A 237 



(_/) R. natans. A form with floating leaves mostly ovate, or at 

 least broadly elliptical, often found growing in muddy-bottomed 

 lakes and pools. It has never been seen in flower to my know- 

 ledge. I once sent this to Mr. Bennett of Croydon, asking if he 

 thought it was Alisma ranunculoides with floating leaves. He 

 suggested that it was a form of R. Flammula ; and since then 

 I have had ample proof that it is so. 



(g) R. radicans. A form that, although agreeing very well with the 

 descriptions given of R. reptans, is yet a very different plant. 

 It does radiate for a few times from a common root, but not 

 from the stems more than once. It has the flowers, and nearly 

 the arching habit, of R. reptans ; but the rooting nodes and con- 

 stricted and very perceptibly tapering stem show at once its 

 Flammula relation. The leaves as a rule are obtuse. This is 

 what I consider the form sent out by the Bot. Ex. Club of the 

 British Isles in 1886 as R. reptans, Linn. It seems to me to 

 be a hybrid between R. reptans and JR. pseudo-reptans, and 

 grows plentifully among them on the shores of Loch Leven. 

 The great objection to this opinion is that it is common where 

 R. reptans is not found. 



(//) R. reptans. This form differs from all the preceding in that, 

 when a well grown plant is taken up, it is difficult to tell which 

 root is the primary one, the roots being fibrous, not succulent, 

 every rooted node supporting in appearance an independent 

 plant, which cannot be disengaged without destroying the parent 

 stem. The stems are round, never erect, and never swollen 

 above the node ; and the difference in thickness between ad- 

 joining nodes is scarcely perceptible. The leaves as a rule are 

 acute. The achenes are compressed, with a short, broad beak. 



(z) R. tridenticulatus. This is, so far as I know, a new form. It is 

 not at all common, and is possibly confined to Scotland. It 

 differs from all the others shown by having a rosette of leaves 

 at its primary root, which leaves have long petioles. The 

 lamina is linear-elliptical, and has on either margin, as a rule, 

 from one to three very prominent teeth. Its stems are decum- 

 bent, then erect, not rooting at the nodes. The stem-leaves 

 also have long petioles and linear-lanceolate laminae, except in 

 the root-leaves. This form is almost identical with the form 

 above named R. suberectus. It was found beside Loch Leven 

 in 1878, and beside Loch Tay in 1893. 



Generally speaking, these forms, excluding R. reptans, are 

 treated by botanists as beneath special notice. Hence it is 

 commonly stated that when the stems are too weak to sup- 

 port themselves they fall down, root at the nodes, and become 



