136 • A Miscellany 



by Lang (1948) should be a perfectly attainable goal, and well worth 

 the effort. 



FLOWERING AND DEATH 



In addition to providing a melodramatic heading, the relation- 

 ship between these two processes is sufficiently intimate in some 

 plants— the monocarpic— to warrant some further mention. 



One reason for death following heavy flowering might be 

 simply morphological. If all the shoot meristems are converted to 

 determinate structures, vegetative growth cannot continue— at least 

 without the formation of adventitious buds. Whether this complete 

 conversion of all meristematic areas into flowers ever actually occurs 

 is of course another question, but the possibility can be envisaged. 



The usual explanation of death following flowering and fruit- 

 ing is nutritional— death is seen as the result of metabolic patterns 

 in which the flowers, fruits, and seeds in some way compete so 

 successfully with the rest of the plant for energy sources and other 

 materials that death is the eventual result. The evidence is largely 

 from observations, so often made, that the life of annuals can be 

 prolonged by removing flowers and young fruits. However, it has 

 recently been pointed out that there may be other explanations for 

 such results, such as the production of inhibitors at various stages 

 of reproductive development. For example, senescence in staminate 

 spinach plants can be put off for a long time by removing the 

 flowers. Since no fruit or seed could be set by these plants under 

 any circumstances, and the staminate flowers themselves do not 

 appear to contain large amounts of reserves, the simple nutritional 

 hypothesis seems very weak here (Leopold et al., 1959). The article 

 cited contains additional experiments and references on this topic, 

 which is largely unexplored. 



It has already been mentioned many times that there are close 

 relationships between flowering and vegetative growth habit, de- 

 pending upon the plant; it is usually unclear whether a given 

 growth change is directly related causally to flowering or whether 

 both express another underlying condition. The relationship in 

 monocarpic plants thus represents another, and surely the ultimate, 

 aspect of this more general problem. 



