IV. GRADES OF SPECIES. 39 
Now, it may be asked, with which grade in the above treble or 
quadruple series should Rununculus Ficaria be associated as a 
co-equal? Mr, Bentham made it the equal of his very inclusive 
RR. aquaticus (A). Sir James Smith made it the equal of the 
Linnean hederaceus and aquatilis as two disunited species (1 and 2), 
—a view to which Mr. Bentham himself has subsequently gone 
back. Professor Arnott makes it the equal of hederaceus, Lenor- 
mandi, fluitans, circinatus, and also of aquatilis Linn.) Professor 
Babington makes it the equal of the former four; also (instead of 
aquatilis) the equal of heterophyllus, floribundus, peltatus, tricho- 
phyllus, Drouetii, etc. 
In further illustration, let us suppose a botanist to follow the 
nomenclature of Bentham’s Handbook, first edition, and to print 
the name of R. aquaticus in a list of plants seen in some given 
country or place, it would be impossible for a reader to know 
whether the Linnean hederaceus or the Linnean aquatilis was 
intended ; either or both might be there, and every form of both, 
or only one form of either. Another botanist, avowedly using 
Smith’s English Flora, might print nearly the same name in like 
manner ; and here we should know that he intended some form of 
the Linnean aquatilis, exclusive of hederaceus and its sub-forms, 
although we should still be uncertain whether heterophyllus, panto- 
thria, fluitans, or circinatus,—or some one, two, three, or all of 
these,—had been found in the district under report. Still less 
should we be prepared by the name of R. aquatilis (Linn.) or 
aquaticus (Benth.) to decide whether all or any of the sub-forms 
heterophyllus, floribundus, peltatus, trichophyllus, Drouetit, etc., 
had been found; since our Benthamian or Linnean botanist might 
have intended to record fluitans or circinatus only by his use of 
the name Ranunculus aquatilis or aquaticus. 
A practical consequence of much importance to works like the 
present one, arises out of these diverse ways of dividing or 
grouping, of segregating or aggregating plants. As the phyto- 
geographer consults many recorded localities and lists of plants, 
written by various botanists at widely different dates, or by those 
severally using the same name to express various different unions 
