MYCOLOGY DURING THE PAST FIFTY YEARS 571 



by the more complex and elaborated entities among the higher forms of plant 

 life. In construction, they range from single-celled forms and simple aggregates 

 and associations through ascending hierarchies to the highest architectural 

 types involving the branching filamentous pattern which is their predominant 

 structural feature. This pattern has marked advantages since it avoids the 

 surface-volume-ratio problem which presents serious difficulties in the sphere 

 and in the massive solid, gives tremendous effective surface for physiological 

 and other activities, and affords notable facility in its growth. It provides also 

 for continued growth which may outrun senescence, ever advancing centrif- 

 ugally yet in an active condition with intercommunication between all its 

 parts, and it permits the weaving, massing, aggregating, and growing together 

 of these filaments into a great diversity of massive forms. Yet the filaments 

 may readily break up into segments and cells which may serve as reproductive 

 entities, or by simple modification may lead to the more specialized develop- 

 ment of such in positions favorable for production and distribution. And 

 finally, fusion between filaments, parts of filaments, and specialized develop- 

 ments therefrom can achieve the bringing together of different types of cells 

 and nuclei, accomplishing the essential feature of sexual reproduction, while 

 other developments provide suitable conditions and structures for the corollary 

 event of meiosis with efficient provision for the production of vast numbers of 

 propagative entities to ensure the expression of all possible combinations which 

 may have evolutionary value. 



Among investigators with the requisite scientific imagination, perceptive 

 discernment, and experimental ingenuity, there has been a growing apprecia- 

 tion of the suitability of fungi as material for investigation, and the happy 

 combination of the ingenuity of the investigator and the suitable potentialities 

 of the fungi for investigation has yielded a striking amount of enlightening 

 results on problems and questions of fundamental significance. 



Progress in mycological work contributive to Botany has been in general 

 a steady, continuing, step-by-step progress, with, in some instances, the rapid 

 advances, the notable leaps forward, which are the exciting episodes in any 

 branch of human endeavor. Continuing progress of the cumulative type has 

 proceeded on all fronts as a result of the interest, devotion, and enthusiasm 

 of the many productive workers in all the diverse areas which mycology com- 

 prises. The more striking and spectacular contributions, derived from the 

 steady accumulation of results as their precursors, have often been initiated 

 and quickened into rapid advance by special instigating factors. In some in- 

 stances it was serendipitous observation which triggered a chain of events, 

 as in the case of Fleming's recognition of the possible significance of the zone 

 of inhibition around a contaminating fungus setting in motion the train of 

 events that led to the startling developments of the field of antibiotics. In 

 other instances, the advances were in response to the imperative challenge of 

 demanding necessity, as in the case of the response of the research and de- 



