178 SIGNIFICANCE OF MALFORMATIONS IN ORGANOGRAPHY 



that the increase in number of the perianth-leaves has been occasioned 

 by the more or less early transformation of the stamens into petals, and 

 as the number of the stamens is large the function of the staminal 

 apparatus is not disturbed. From such flowers the passage to com- 

 pletely double ones in which all the stamens are transformed into petals 

 is a gradual one ; but we must designate these double flowers as mal- 

 formations, because in them a strong departure from the normal develop- 

 ment has taken place with which is combined a disturbance of function. 



Darwin's definition is ' By a monstrosity [malformation] I presume 

 is meant some considerable deviation of structure, generally injurious, or 

 not useful to the species V Moquin-Tandon, the author of one of the best 

 books upon malformations in the Vegetable Kingdom, says'-, 'By an 

 anomaly we mean any extraordinary modification in the formation or 

 the development of organs, irrespectively of any influence upon health.' It 

 is however quite impossible to separate malformations from the appear- 

 ances of disease. We speak of disease usually when we know the cause 

 of the malformation, for example, the deformity of the buds of the spruce, 

 caused by the insect Chermes Abietis, is an evident malformation, but 

 at the same time it is also a symptom of a disease which has an injurious 

 influence upon the health of the tree only when it is general over the 

 tree. In like manner there can be no doubt that the phyllody of flowers, 

 a favourite domain of teratology, is a symptom of disease ; it is a misbirth, 

 the cause of which we do not know in most cases. 



What is normal in one plant we must in another regard as abnormal. 

 In Vicia Faba it occasionally happens that the leaves are absent, but 

 their stipules develop strongly, and, as I have shown, do so in con- 

 sequence of the failure of the leaves. This is certainly a malformation. 

 It is however the normal state in Lathyrus Aphaca. In this plant the 

 foliage- leaves in the upper part of the stem are transformed to tendrils ; 

 but we occasionally observe individuals which possess fully formed leaves 

 instead of arrested ones, in, for example, the form known as ' Lathyrus 

 Aphaca unifoliatus.' This feature must certainly be considered a reversion, 

 but if we start from our ' normal ' Lathyrus Aphaca of to-day it is a mal- 

 formation just as are the spikelets which sometimes appear upon the 

 sterile bristle-like twigs of Panicum italicum 3 . In many grasses, especially 

 species of Poa, the flowers are arrested and the axis of the spikelet grows 

 into a vegetative shoot which separates at a later period from the mother- 

 plant ; this again is a malformation. But when races have become 

 developed in which this malformation is hereditary, the condition has 



1 Darwin, Origin of Species, Chapter u, first paragraph. 



2 Moquin-Tandon, Elements de teratologie vegetale. Paris, 1841, p. 1 8. 



3 The occurrence of ' Panicum italicum setis inflorescentiae spiculiferis ' has been often described. 

 See A. Rraun, in Monatsb. d. Berliner Akad. d. Wissensch. 1875, p. 258. 



