RHYTHMS IN PLANT LIFE 67 



Of interest is the neat way in which the young leaves 

 are packed within the bud, being usually twisted in a 

 spiral, corresponding to the spiral which the leaves eventu- 

 ally exhibit when they are unfolded and outspread upon 

 the shoot or branch. 



The prime conditions of the unpacking of buds are, of 

 course, to be found in the Spring sunshine and the Spring 

 rain. Under the influence of increasing warmth the 

 water from the soil ascends to the sleeping buds and recalls 

 the cells to activity. These swell, become active, and 

 multiply, and the pressure from within bursts the scales 

 outside, which in dying away have saved the tender life 

 within. 



MULTIPLICATION 



One of the fundamental and far-reaching facts about 

 the life of plants in Spring is much less familiar than the 

 germination of seeds, the rise of the sap, and the opening 

 of buds. It is the extraordinarily rapid multiplication 

 of minute water-plants of unicellular Algae in particular. 

 The importance of this lies in the provision of an almost 

 exhaustless food-supply for water animals. The complex 

 organic substances which the plants build up, with the 

 sun's aid, from air, water, and salts in solution, become 

 part and parcel of one animal after another through long 

 series of reincarnations. As to the rapidity with which 

 a pond or a lake becomes peopled with minute plants, 

 when Spring sets in, we can form little conception, for a 

 single one may become a thousand in two or three days, 

 and a million by the end of a week. In a particular 

 case, Professor Zacharias notes that within ten days the 

 numbers may be increased sixfold, and that there may be 

 over 70,000 (72,950) in a single litre. 



