362 STATE HORTICULTURAL SOCIETY. 



delicately constructed and beautifully colored envelopes. These assist 

 in protecting the organs within, but their principal function is to attract. 

 Outside the petals are the sepals, another set of leaves whose mission is 

 to protect. This, in brief, is a type of flower. There are thousands of 

 variations, but all amenable to the general conception that a flower is a 

 modified shoot, with its parts arranged in whorls or sets and corre- 

 sponding to the arrangement of the twig, and as such may be transformed 

 from one series to the other. 



Prof. Bailey, in his excellent book on plant breeding, emphasizes the 

 distinctive difference between pollination and fertilization, terms which 

 are often used somewhat loosely. Pollination, as defined by him, is the 

 artificial or manual part of the work of carrying or transferring the 

 pollen from one flower to another. Fertilization is the work of the pollen 

 itself, and means the germination of the pollen, growth of the pollen tube 

 down through the connective tissue of the style to the cavity of the 

 ovary, where fecundation takes place. The stimulus .which the process 

 of fertilization imparts to the ovule, and which results in the develop- 

 ment of seed, is also transmitted to the tissues of the ovarian wall. We 

 recognize this in the rapid modification of the flowers of apples and pears 

 after fertilization takes place. With the development of the seeds, the 

 carpels surrounding these become modified from green tissue into ripened 

 fruit. I 



The reasonableness of the statement that it is the temperature of the 

 surrounding air that ctiiefly determines the temperature of twigs and 

 branches, as well as the more delicate parts, such as fruit buds and leaf 

 buds, will be at once admitted ; yet many people speak vaguely about the 

 benefits of mulching trees heavily after the ground is frozen, in order to 

 hold the frost in the ground in the spring, and by this means retard the 

 opening of the blossoms. One experiment of this kind, if fairly tried, 

 will convince the most skeptical that the buds, with their store of pre- 

 pared food, respond toward spring, after their accustomed winter's rest, 

 to the temperature of the air which surrounds them, regardless of the 

 temperature or condition of the soil. A study of the effects of frost upon 

 plant tissue is exceedingly interesting. 



In looking into the literature on this subject, I have found in '' Diseases 

 of Trees," by Prof. Hartig of Munich, German}-, many valuable facts and 

 observations which I may be allowed to present. Considering the action 

 of frost upon what we call dormant wood, he says: "Death of a plant 

 under the action of frost during winter bears a close resemblance to 

 effects of drought in tissues." Severe frost, as before stated, abstracts 

 moisture, and in proportion to its severity. The cells may, therefore, die 

 in winter when this deficiency of water exceeds a certain limit. Hartig 

 further says: "A change is induced in the molecular constitution of the 

 protoplasm, which is rendered incapable of retaining any considerable 

 quantity of water. This change is brought about probably by the forma- 

 tion of new molecular groups." "Should the critical limit of drought not 

 be passed, the cell gradually reabsorbs and life functions may proceed. 

 If this critical point is passed, the cell can not reabsorb, and it withers. 

 The same holds true with regard to the action of frost, as inducing a loss 

 of water. The cell will bear a certain amount of frost, such as will not 

 disturb the molecular arrangement of the protoplasmic particles; but, 



