THE FLO WEE 215 



In most cases we are justified in regarding the reproductive 

 organs as leaves modified for a very definite object, and the 

 stamens have therefore been termed staminal leaves, while the 

 pistil may be looked upon as built up of one or more carpellary 

 leaves or carpels. The most important part of the stamen 

 are the pollen sacs, which run parallel on either side of the 

 median connective. Looking upon it as a modified leaf struc- 

 ture, the stamen represents a leaf consisting of a long and 

 delicate stalk {filament), and thick cylindrical blade {anther), 

 into which the stalk is continued as a connective, the top of 

 which often projects above. On both sides of this connective lie 

 the pollen sacs, two of which go to form each half of the anther. 

 The stamen has therefore four pollen sacs. The tissues in the 

 middle of each pollen sac will undergo certain divisions, and 

 the cells which ultimately result from these divisions round 

 themselves off one from another. They become covered by 

 a thick outer coat, which is often curiously sculptured, and 

 each cell is termed a pollen grain. These are generally libe- 

 rated by the longitudinal splitting of the anther, which opens 

 the pollen sacs. In some cases the anthers open by pores 

 {Ericaceoe). 



The stamens have, therefore, in many respects, the same 

 structure as the normal green leaf, and we must, therefore, not 

 be surprised if at times, when there is a considerable tendency 

 for the development of green leaves, the stamens themselves 

 should become transformed into green leaves. 



The anthers in that case do not become cylindrical, but are 

 thin and expanded, and coloured green. The loss of the 

 cylindrical shape of the anther generally entails the loss of the 

 power of forming pollen, and the stamen becomes a true green 

 leaf. This retrogressive transformation is at the bottom of 

 most doubling of flowers. 



The female organ or pistil can be very well seen as the 

 central structure of the flower of the Tulip or the Cherry. It 

 consists of a dilated basal portion, the ovary, a long tube- 

 like prolongation, the style, with a knob-like or lip-like ter- 

 mination, the stigma. We may conceive it to be formed by a 

 number of sessile leaves (carpels), the blades of wliich are drawn 

 out into points, and the margins of which have become fused 



