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tliem than are found between generally received species, but which are, never- 

 theless, too constant in their characters to be considered as merely varieties." 

 It is a very convenient term when used merely for groxiping plants as to the 

 true relation of which thei-e is a question. Judging, however, from local 

 experience chiefly, and therefore at gi-eat disadvantage, I venture to doubt 

 whether the term " sub-species", as applied to the different forms of B. 

 aquatilis, conveys an exact notion of their relationshij). For if the variations 

 which distinguish them are permanent under all conditions of the plant, and 

 appear to have always existed, they must be separate species, however small 

 the difference between them ; and, on the other hand, if they are neither 

 original nor permanent forms, they must be merely varieties, however great 

 their diversity, 



"With the view of forming an opinion on this point in relation to the 

 various forms of the Ranunculus aquatilis of Linnceus, I searched the waters of 

 one locality. "Within half a mile of Garnons, I fovind specimens of every form 

 of the plant which could possibly have grown there. There were the so-called 

 species and sub-species fliiitans,peltatus, florihundus, heterophylbis, Drouetii 

 and trichophyllus. There was, I thought, a distinct character in the water of 

 the habitats of these different forms, but u^ion this point I should be glad of 

 further opportunity of examination, and also of the experience of other 

 observers. In that difference of character I thought I saw sufficient provo- 

 cation, so to speak, for all the variations in the forms of the plant, esi^ecially 

 in such a variable genus as we know this to be. My specimens of the ordinary 

 forms of aquatilis were from ditches of clear stiU water. In a pool through 

 which a spring ran, grew the sub-species hcteropht/llu^. It. Drouetii grew in a 

 pool which was thick with whiteish mud from land drains. Trichophyllus 

 was in a large clear pool. In the strong currents of the Wye which drag and 

 keep the plaat beneath the surface, and are subject to frequent changes of 

 level, there was of course B. fiuitans, but even here I found on-? specimen with 

 a true floating leaf, caused, I have no doubt, by accidental protrusion of the 

 end of a single stem abovethe surface in very still water. The names of the 

 above forms are given to them by the best authorities to whom the plants have 

 been submitted, including Mr. Boswell Syme. I would not myself take any 

 responsibility about them, for in common with others whom I have consulted, 

 I have found the greatest diiBculty in applying the distinctive characters 

 found in books to actual specimens — such distinctions as those founded on 

 the submerged leaves which either collapse or remain divaricate when taken 

 out of the water — the extent to which the extremity of the stem projects 

 above the surface (which seems to be a question of specific gravity.) The 

 occurrence or not of floating leaves (which probably depends upon similar 

 causes) all seems insufficient to found any reliable distinction upon, and I 

 believe they are found unreliable in practice. When the stems of aquatilis 

 turn down again into the water after flowering, the submerged leaves are again 

 produced above the floating leaves. When jluilans grows upon mud, from 



