I860.] Abnormal and Normal Formations in Plants. 225 



more value as they have been made without any reference to theoretic 

 views.* 



Another difficulty in distinguishing the abnormal from the normal 

 in plants, arises from the fact that wliat is unnatural or unusual in one 

 plant, is the common condition in another nearly allied plant. In illus- 

 tration of which several instances were cited ; and one in particular, 

 which led Herr S. Reissek, in some measure, to anticipate the views of 

 Mr. Darwin. The changes took place in a species of Thesium, affected 

 by a parasitical fungus, in consequence of which apparently, the plant 

 underwent many changes, some of which caused it to assume many of 

 the characteristics of allied species and even genera. " Suppose," says 

 the author, " the condition originally caused by the fungus to become 

 constant in the course of time, the plant would, if found growing wild, 

 be considered as a distinct species, or even as belonging to a new genus. 

 Nature appears to have set up a fingerpost, to show the way in which 

 species and genera may have been formed out of a previously existing 

 type," &c.| Here, however, there is no reference to the ceaseless 

 process of natural selection, and of very gradual change. Another cir- 

 cumstance which adds to the perplexity that is felt in distinguishing 

 the normal from the abnormal in plants, is that irregularity of growth 

 can hardly be considered abnormal, because it is in many instances a 

 constant condition ; the health of the plant is in no wise impaired, the 

 irregularity does not exist at first, but arises during development, and 

 it is subject to definite laws. 



Certain changes may be physiologically abnormal, because they 

 interfere with the due fulfilment of the functions of the part affected ; 

 and yet morphologically they can hardly be considered abnormal, 

 because they do not violate any of the laws of morphology, and are 

 caused perchance by a mere reversion to a simpler form. 



Reference was then made to the classification of malformations in 

 plants, adopted by M. Moquin Tandon, in his standard work on the 

 subject, in order to exemplify the impossibility of drawing a line 

 between what should and should not be deemed a malformation, for 

 the reasons already mentioned. Even in the class of Malformations 

 grouped under the head of " Deformity," the change was so slight 

 as not to interfere with the physiological functions, or it was one 

 which occurred naturally in other plants. " Peloria," or that change 

 whereby a flower usually irregular becomes regular, may occur in two 

 ways — one where the flower becomes regular by the increase of its 

 irregular portions, so as to restore the symmetry, as in the Pelorian 

 varieties of the common Linaria ; the other, almost entirely over- 

 looked, is where the flower preserves throughout life its original 

 equality of proportions. The calyx of the double Tropceolum affords 

 an illustration of this. The calyx of the simple form is coloured, with 

 its upper sepal prolonged in the shape of a spur ; in the double variety 



• Buckman, Rep. Brit. Assoc. 1857. 

 t Lumsea, Vol. 17, 1843. 



