CHAP, in.] the Dogma of Constancy of Species. i~,i 



would be obliged to bring the Algae, Rhizocarps, Vallisnerias, 

 water Ranunculuses, Lemna, etc., into one group. It is very 

 important for the existence of a plant whether it grows upright 

 of itself, or climbs upwards by the aid of tendrils or of a twining 

 stem or otherwise, and accordingly we might on Lindley's prin- 

 ciple collect certain ferns, the vine, the passion-flower, many 

 of the pea kind, etc., into one order. It is obvious that Lind- 

 ley's main axiom of systematic botany appears in this way 

 utterly unreasonable ; yet by this principle he judges of the 

 systematic value of anatomical characters, those of the embryo 

 and endosperm, of the corolla and the stamens, everywhere 

 laying stress on their physiological importance, which in these 

 parts has really little systematic value. This mode of pro- 

 ceeding on the part of Lindley, compared with his own system, 

 which with all its grave faults is still always a morphologically 

 natural system, proves that like many other systematists, he did 

 not literally and habitually follow the rules he himself laid 

 down, for if he had, something very different from a natural 

 system must have been the result. The success which was 

 really obtained in the determination of affinities was due chiefly 

 to a correctness of feeling, formed and continually being per- 

 fected by constant consideration of the forms of plants. It 

 was still therefore virtually the same association of ideas as in 

 de 1'Obel and Bauhin, operating to a great extent unconsciously, 

 by which natural affinities were by degrees brought to light ; 

 and men like Lindley, of pre-eminent importance as system- 

 atists, were, as the above examples show, never clear about 

 the very rules by which they worked. And yet in this way 

 the natural system was greatly advanced in the space of fifty 

 years. The number of affinities actually recognised increased 

 with wonderful rapidity, as appears from a comparison of the 

 systems of Eartling, Endlicher, Brongniart, and Lindley, with 

 those of De Candolle and Jussieu. Nothing shows the value 

 of the systems thus produced before 1850 as classifications of 

 the vegetable kingdom more forcibly than the fact that a clear 



