288 



"collapse into a pencil when taken ont of the water." Its floating leaves are 

 almost circular, inclined to be divided into five segments, and the margins are 

 formed of straighter lines than in the last sub-species. (3) It. Droaet'd is a 

 slender plant. It has seldom any floating leaves : its submerged leaves collapse 

 when drawn from the water. (4) R. trichophyUus seldom produces floating 

 leaves, its submerged leaves are "short, divaricate, compaiatively rigid." 

 There are other minute distinctions between these varieties founded on the 

 flowers and seeds. 



Species 4 is B. Baudotii, which grows chiefly in brackish water, and, so far 

 as I can judge, has the thickened fleshy form which one expects to see in the 

 plants of such a locality. One variety of it, B. confusus, grows also in fresh 

 water. 



The remaining members of this s^ow^—triparUtus (one variety of which 

 has been found in England), Lenormandi, and hederaccm—axe less closely 

 allied in appearance to the preceding species, but the bond of union between 

 them is closer than would be inferred from an inspection of our British 

 species only. 



This being, perhaps, the most clear and intelligible arrangement for 

 showing the different forms, we may now look at the way in which they have 

 been dealt with by other eminent botanists. In the older books four varieties 

 of Banuncuhts a^«a<i7(.? are recognised. These seem to be— 1st, the common 

 form, which has floating and submerged leaves ; 2nd, that which has submerged 

 leaves only ; 3rd, i?. Jiuitana; 4th, R. circinatus. Mr. Babington, after having 

 in preWous editions of his manual treated the forms of aquatitiii as varieties 

 only, has in his last edition elevated them to the rank of distinct species, so 

 that the whole grouji now stands as follows : — 



B. trichophyUus B. Ban'iotii B, circinatus 



Drouetii fiuribundus fuitans 



heterophyllvs licltaius ccefiosus 



confusus tripartitus hedm-aceus 



Now Mr. Bentham considers these twelve different forms to be but 

 varieties of one species, upon which he makes these remarks ; — " Many of the 

 forms it assumes are striking and have been distinguished as species, but the 

 characters, although to a certain degree permanent, appear at other times so 

 inconstant, and even to depend so much on the situation the plant grows in, 

 that we can only consider them as mere varieties." In his last edition he 

 recognises liederaceus as a distinct species, though somewhat against liis 

 private judgment, remarking that varieties occur in southern Europe which 

 ally it to aquatilis. 



Here are three very different views put forth by botanists of the first 

 rank, and two of them at least must fail to convey an idea of the true relation 

 of the plants to each other. Aie they several species or one species ? or are 

 several of them to be considered as " sub-species" ? The last term is appUed 

 by Mr. Lyne to "plants which have less strongly marked differences between 



