STAMENS. 75 



In polypetalous corollas, the number of stamens is sometimes 

 much greater. When they equal the divisions of the corolla, they 

 usually alternate with these divisions. When the number of stamens 

 is double the divisions of the corolla, half of the stamens are usually 

 placed in the intervals of the divisions, and the remaining half bf^ 

 fore each lobe of the corolla, corresponding to the intervals in the 

 divisions of the calyx. If any of the stamens are barren or without 

 anthei-s, they will be found to be those which are placed before the 

 lobes of the corolla. 



In commencing the analysis of flowers according to the Linneean 

 system, you learned that the number of stamens, their posilion, rela- 

 tive length, and connexion, taken either singly or in combination, 

 afford certain and distinctive marks for purposes of classification. 



In the first place we find the stamens differing in number, in dif- 

 ferent plants; some plants have but one, some two, and so on till we 

 come to ten ; when they have more than ten, we find the number in 

 the same plant varies, and therefore we cannot depend on this cir- 

 cumstance for further classification. 



We then resort to position, and consider whether the stamens are 

 inserted upon the calyx or the receptacle, thus furnishing an eleventh 

 and a twelfth class. 



Inequality in the length of stamens, when they are either four or six, 

 furnishes us with a thirteenth and fourteenth class. 



The connexion or union of stamens gives us the fifteenth class, 

 where the filaments of the stamens are united in one set; the six- 

 teenth class, where they are in two sets ; the seventeenth, where the 

 anthers of the stamens are united. 



The three remaining classes of phenogamous plants are distin- 

 guished by the position of the stamens with respect to the pistils. In 

 the eighteenth class the stamens stand on the pistil ; in the nineteenth 

 the stamens and pistils are on separate flowers on the same plant ; 

 in the twentieth they are on separate plants ; and in the twenty-first 

 they are invisible. 



Parts of the Stamen. — The Filament, is so called from filum, a 

 thread. Filaments vary in their form ; some are long and slender, 

 as in the pink ; others are short and thick, as in the tulip. They are 

 usually smooth, but in the mullein they are bearded; in the spider- 

 wort ( Tradescantia) they are covered with down. In most cases a 

 filament supports but one anther, but sometimes it is forked and 

 bears two or more ; in some instances, many filaments have but 

 one anther. When the filaments are enclosed in the tube of the corolla 

 they are said to be inserted, when they extend out of it, exserted. In 

 some cases the filament is wanting, and the anther is sessile, or im- 

 mediately attached to the coralla. 



In double flowers, the stamens, which seem to be intimately con- 

 nected with the parts of the corolla, are changed to petals. This is 

 the effect of cultivation, which, by affording the stamens excess ol 

 nourishment, causes them to sweU out, and thus assume the form of 

 petals. In some double flowers almost every trace of the stamens 

 disappears; in others, it is easy to perceive the metamorphosis 

 which they have undergone, as they retain something of their origi- 

 nal forms. In double flowers the anthers usually disappear, which 

 shows that the filaments have absorbed all the nourishment. In 



Situation of the stamens with respect to the divisions of the corolla— Stamens used 

 for purposes of classification— Differ in number— In their position— Stamens differ in 

 length— In connexion— In position with respect to the pistil— Parts of the stamens- 

 Filament- Stamens changed to petals. 



