XXXVIU INTRODUCTION. 



Flowers usually very irregular, may, on certain individuals, lose more or less of tlieir 

 irregularity, or appear in some very different shape. Spurs, for instance, may disap- 

 pear, or be produced on all instead of one only of the petals. 



One part may be occasionally added to, or subtracted from, the usual number of 

 parts in each floral whorl, more especially in regular polypetalous flowers. 



Plants usually monoecious or dioecious may become occasionally hermaplu-odite, or 

 hermaphrodite plants may produce occasionally unisexual flowers by the abortion of 

 the stamens or of the pistils. 



Leaves cut or divided where they are usually entire, variegated or spotted where they 

 are usually of one colour, or the reverse, must also be classed amongst those accidental 

 aberi'ations which the botanist must always be on his guard against mistaking for spe- 

 cific distinctions. 



