Most irregular flowers owe their irregularity to an unequal development of some of their organs as compared with that of others. When such flowers become exceptionally regular they do so either because development does not keep pace with growth, and a regular flower is thus the result of an arrest of the former process (regular peloria), or because the comparatively excessive development, which usually occurs in a few parts is, in exceptional cases manifested by all, hence the flower becomes regular from the increase in number of its irregular elements. These latter cases, then, are due to an excess of development, hence the application of the term pleiomorphy. It must be understood that mere increase in the number of the organs of a flower is not included under this head, but under that of deviations from the ordinary number of parts. FOOTNOTES: [231] [Greek: Pleios-morphosis]. CHAPTER I. IRREGULAR PELORIA. The term peloria was originally given by Linne to a malformation of _Linaria vulgaris_, with five spurs and five stamens, which was first found in 1742 near Upsal. This was considered so marvellous a circumstance that the term peloria, from the Greek [Greek: pelor], a prodigy, was applied to it.[232] After a time other irregular flowers were found in like condition, and so the term peloria became applied to all cases wherein, on a plant habitually producing irregular flowers, regular ones were formed. The fact that this regularity might arise from two totally different causes was overlooked, or at least not fully recognised, even by Moquin-Tandon himself. Where a flower retains throughout life the same relative size in its parts that it had when those parts first originated the result is, of course, a regular flower, as happens in violets and other plants. This kind of peloria may for distinction sake be called regular or congenital peloria (see chapter on that subject); but where a flower becomes regular by the increase in number of its irregular portions, as in the _Linaria_ already alluded to, where not only one petal is spurred, but all five of them are furnished with such appendages, and which are the result of an irregular development of those organs, the peloria is evidently not congenital, but occurs at a more or less advanced stage of development. To this latter form of peloria it is proposed to give the distinctive epithet of irregular.