10 N. H. Agricultural Experiment Station [Bulletin 274 



sists of an anther, a small yellowish sac attached to the end of a slender 

 \vhite filament or stalk. The anthers contain thousands of minute rounded 

 cells known as pollen grains which contain sperms, the male elements of the 

 flower. 



The cultivated varieties of apples ordinarily have 20 stamens, although 

 occasionally small petal-like organs may be found to have replaced some of 

 the stamens, and sometimes the filaments of the stamens may appear petal- 

 like. 



Each pistil in the apple consists of five slender green stalks which are 

 coalesced in the lower part to form a single cylinder of tissue, usually more 

 or less covered with fine hairs. The five individual parts of the pistil are 

 called styles. Each style is capped with a stigma. The stigma has a papil- 

 lated surface (see Fig. 7.). It is on this surface that the pollen grains are 

 left by the insects and this is the place where the germination of the pollen 

 grains takes place. 



The female portion of the flower consists of three parts : ovary, style 

 and stigma. The ovary is the basal portion of this apparatus. It lies im- 



Fig. 6. Cross section of mature anther of Mcintosh (35x). a. Fila- 

 ment attachment, b. Cavity containing pollen grains, c. Integuments 

 which open out as the anthers dry, exposing the pollen. 



bedded in the tissues beneath the calyz and contains the ovules, occasionally 

 20 in number ])ut in most varieties 10. Each ovule contains a female element 

 or egg cell, so that with perfect fertilization it is possible in some varieties 

 to develop 20 seeds in the apple. Fertilization and complete development 

 of all the ovules into seeds seldom occurs in any apple, five to 10 seeds 

 being the usual number. 



Fertilization of the Egg Cells: 



To fertilize the 20 ovules of a Mcintosh apple ovary, at least 20 dififer- 

 ent pollen grains are needed. As it happens only a few of the thousands of 

 pollen grains ])roduce(l ultimately reach an ovule to effect fertilization. 



Individual pollen grains when mature are crowded closely together in 

 the anther. When the flower bud opens and the anther is exposed to the 

 sun and dry air, it splits open leaving the pollen exposed. 



This pollen looks to the unaided eye like a fine, powdery-yellow dust. 

 Each grain is too small to be seen as an individual by the unaided eye. The 

 pollen grain (Fig. 8A) when saturated with water is slightl}- triangular in 



