3 



It IS a matter of common observation that buds, and par- 

 ticularly those producing blossoms, open with rapidity, burst, 

 as it is termed, and there is no corresponding formation of 

 substance out of which to grow at that period in the life of 

 the plant. It follows, therefore, that there must be a reserve 

 of formative material stored somewhere in the plant for the 

 purpose of supplying the needed nourishment at this im- 

 portant and dependent annual period in the life of every tree 

 and shrub. If we should consider seeds as to their minute 



structure, we should find that besides the plantlet there is 



frequently a large mass of lifeless substance stored in contact 

 with the embryo, as in corn, and often enveloping it. This 

 liquifies in germination and yields to the unfolding plantlet 

 ample support until it can thrust its roots into the soil, lift its 

 fresh leaves up to the air and sunshine and shift for Itself. In 

 many seeds, as the bean, the embryo is large and gorged with 

 the food-material that the parent plant has provided for it. 



There are many points of agreement between a seed and 

 a winter bud. Both are constructed for a period of inactivity, 

 and protected from untoward influences by thick layers of 

 impervious substance. Both start into growth under the 

 same quickening influences of vernal warmth and moisture, 

 and in fact the buds of some plants, as those of the Indian 

 shot-lily, regularly become detached, fall to the ground and 

 are the starting-points of ncw^ plants. This is an important 

 point in proof of the similarity of structure of seeds and buds. 

 We should, therefore, naturally infer that at some place in 

 every bud, or near by, there is a reservoir of those substances 

 that are needed for its initial growth at least. A study of 

 this point is now before us.* 



* Tlie investigations, the results of which are herein presented, were begun 

 during the winter of 1SSS-S9, when, continuously for two months at the Iowa 

 Experiment Station, the reserve Ajod-substances in apple-twigs were studied 



. •«««» ■*' -.- ^-- -. 



in a score or more sorts, including a wide range of hardy and tender varieties. 

 The results as then obtained appeared in Station Bulletin No. 4. During 

 the past year, in spring, summer, autumn and winter, the work has been ex- 

 tended to include a large number of species of ligneous plants and the 

 roots of many perennial herbs. 



