Multiplication of Extremes 765 



varietal and hybrid characters. Most of them 

 are very inconstant from seed and as a rule, 

 only mixtures are offered for sale in seed-lists. 

 Which of their ornamental features are due to 

 fluctuating deviation from an average is of 

 course unknown. Amaryllis and Gladiolus are 

 surrounded with the same scientitic uncertain- 

 ties. Eight or ten, or even more, species have 

 been combined into one large and multiform 

 strain, each bringing its peculiar qualities into 

 the mixed mass. Every hybrid variety is one 

 individual, being propagated by bulbs only. 

 Colors and color-patterns, shape of petals and 

 other marks, have been derived from the wild 

 ancestors, but the large size of many of the best 

 varieties is probably due to the selection of the 

 extremes of fluctuating variability. So it is 

 with the begonias of our gardens, which are 

 also composite hybrids, but are usually sown 

 on a very large scale. Flowers of 15 cm. diam- 

 eter are very showy, but there can be no doubt 

 about the manner in which they are produced, 

 as the wild species fall far short of this size. 



Among vegetables the potatoes afford an- 

 other instance. Originally quite a number of 

 good species were in culture, most of them hav- 

 ing small tubers. Our present varieties are due 

 to hybridization and selection, each of them 

 being propagated only in the vegetative way. 



