Till within a comparatively recent period but little study was given toexceptional formations. They were considered as monsters to be shunned,as lawless deviations from the ordinary rule, unworthy the attention ofbotanists, or at best as objects of mere curiosity. By those whosenotions of structure and conformation did not extend beyond the detailsnecessary to distinguish one species from another, or to describe thesalient features of a plant in technical language; whose acquaintancewith botanical science might almost be said to consist in theconventional application of a number of arbitrary terms, or in therecollection of a number of names, teratology was regarded as a chaoswhose meaningless confusion it were vain to attempt to renderintelligible,--as a barren field not worth the labour of tillage.The older botanists, it is true, often made them the basis of satiricalallusions to the political or religious questions of the day, especiallyabout the time of the Reformation, and the artists drew largely upontheir polemical sympathies in their representations of these anomalies.Linnæus treated of them to some extent in his 'Philosophia,' but it ismainly to Angustin Pyramus De Candolle that the credit is due of callingattention to the importance of vegetable teratology. This greatbotanist, not only indirectly, but from his personal research into thenature of monstrosities, did more than any of his predecessors to rescuethem from the utter disregard, or at best the contemptuous indifference,of the majority of botanists. De Candolle gave a special impetus tomorphology in general by giving in his adhesion to the morphologicalhypotheses of Goethe. These were no mere figments of the poet'simagination, as they were to a large extent based on the actualinvestigation of normal and abnormal organisation by Goethe both alone,and also in conjunction with Batsch and Jaeger.De Candolle's example was contagious. Scarcely a botanist of anyeminence since his time but has contributed his quota to the records ofvegetable teratology, in proof of which the names of Humboldt, RobertBrown, the De Jussieus, the Saint Hilaires, of Moquin-Tandon, ofLindley, and many others, not to mention botanists still living, may becited. To students and amateurs the subject seems always to havepresented special attractions, probably from the singularity of theappearances presented, and from the fact that in many cases theexamination of individual instances of malformation can be carried on,to a large extent, without the lengthened or continuous investigationand critical comparative study required by other departments ofbotanical science. Be this as it may, teratology owes a very largenumber of its records to this class of observers.While the number of scattered papers on vegetable teratology in variousEuropean languages is so great as to preclude the possibility ofcollating them all, there is no general treatise on the subject in theEnglish language, with the exception of Hopkirk's 'Flora Anomala,' abook now rarely met with, and withal very imperfect; and thisnotwithstanding that Robert Brown early lent his sanction to thedoctrines of Goethe, and himself illustrated them by teratologicalobservations. In France, besides important papers of Turpin, Geoffroy deSaint Hilaire, Brongniart, Kirschleger and others, to which frequentallusion is made in the following pages, there is the classic work ofMoquin-Tandon, which was translated into German by Schauer. Germany hasalso given us the monographs of Batsch, Jæger, Roeper, Engelmann,Schimper, Braun, Fleischer, Wigand, and many others. Switzerland hasfurnished the treatises of the De Candolles, and of Cramer; Belgium,those of Morren, &c., all of which, as well as many others that might bementioned, are, with the exception of Moquin-Tandon's 'Eléments,' to beconsidered as referring to limited portions only and not to the wholesubject.