66 HEROES OF SCIENCE. 



essential, and are of secondary importance in 

 classification. Now, in some kinds of plants the 

 stigma and the ovary exist in one individual and 

 the stamens in another. The plant which bears 

 the ovary is called the female, and that which has 

 the pollen-making part is termed the male. Hence 

 it is said that plants have sexes. But in a vast 

 number of plants these organs are combined in the 

 same individual. Linnaeus considered the stamen 

 to be of primary importance, and established eleven 

 classes of plants distinguished by the numbers of the 

 stamens, and these all relate to plants in which the 

 male and female organs are combined in the same 

 individual. Thus the red valerian has one stamen 

 only, and it was classed in monandriay the first part 

 of the word meaning •' one " and the last " male." 

 The lilac has two stamens, and was classed in the 

 diandria — " two male ; " and other plants were 

 classified up to those which have ten stamens, the 

 pink, for instance, as decandria. An eleventh class 

 included all plants which bear flowers containing 

 from twelve to nineteen stamens, such as migno- 

 nette. Then two more classes were invented to 

 comprise — i, plants with twenty or more stamens 

 placed on the calyx, as the cherry ; 2, others with 

 twenty or more stamens which are placed on stalks 

 rising from below the ovary, as in the buttercup. 

 Other classes were formed according to the relative 

 length of the stamens, as in the foxglove and wall- 

 flower, and also from the grouping of the stamens 

 in bundles. Then there were three very important 



