236 ANNALS OF SCOTTISH NATURAL HISTORY 



same species. I was compelled to admit then, and, although 

 I have added other three forms, I must admit yet, that when 

 you take extreme forms some of them seem almost to warrant 

 a claim to specific rank. I have read from time to time the 

 remarks by a few able English botanists on the species. 

 Some of these remarks agree very well with my own observa- 

 tions, while some do not. 



It seems to me, if some one with authority would fix 

 upon a type, and give a description of it that would not 

 apply to all the forms, then we might arrive at some means 

 of resolving the species into distinguishable extreme forms ; 

 and then by filling in the intermediates, collectors could at 

 least satisfy themselves as to whether all the following forms 

 were different states of the same plant. 



My experience would lead me to take them thus : 



(<?) J?. Flammula. A tall slender form having a smooth stem, 

 with all its internodes straight, the swelling at the nodes 

 inconspicuous, and leaves glaucous. This form is common in 

 Scotland, grows well up on mountain sides, and may be found 

 growing with other forms. 



(t>) R. pseudo-reptans. This seems to come very near (a), only it is 

 repent and roots at the nodes. It may be easily distinguished 

 from the following forms by its glaucous leaves, and by the 

 stems not swelling much at the nodes, and seldom bearing 

 more than two lateral branches. 



(c) jR. suberectus. A much-branched form, seldom rooting at the 



nodes, although the stem is prostrate, and rises only when the 

 flower-buds begin to develop. This gives the flowers an um- 

 bellate appearance. This form also has glaucous leaves, of which 

 the blade is much longer than the petiole. 



(d) Jt. petiolaris. That strong-stemmed form described by Mr. 



Marshall in the "Journal of Botany," vol. 27, p. 230. If I 

 understand this form aright, it is nearly erect, and differs from 

 form suberectus in having much thicker stems, strongly ribbed, 

 leaves not glaucous, with channelled petioles, is found only in 

 muddy situations, and grows strongest on peat. I have seen it 

 only in one or two places on the shores of Loch Leven. 



(e) JH. serratus. Almost identical with suberectus, but the stems are 



proportionately shorter and stouter, never rooting, while the 

 leaves are not glaucous, and are strongly serrated, and very 

 long. 



