4'4 



FLORAL COMPETITION AND CYCLES. 



Ki\. i;. ADRIAN WOOUKl'Fl-K-PKACOCK, l-.r..S. 



EvKRV one who studies topographical botany in the modern 

 scientific spirit, attempts to discover ' the reason why " for the 

 presence of every species on the soils it frequents, and in all 

 the localities it prefers. When we are thus engag-ed, we soon 

 discover we require a closer analysis of living nature than any 

 existing botanical work affords. A more flexible method of 

 observing and recording facts than has been employed up to 

 date, will soon collect the mass of information that is required, 

 though for the time being there is little enough of the right sort 

 of floral records in print. As a result of this great deficiency, 

 man}' of the arguments used, and conclusions drawn, in works 

 up-to-date are founded on a misunderstanding of even general 

 laws, and a false appreciation of the simplest facts of nature. 



One of these fundamental mistakes seems to have become 

 crystallized in the following sentence of a modern work. ' The 

 conditions accompanying human operations of which plants 

 seem to take advantage, are (i) the disturbance of the ground, 

 and (2) the unnatural supply of plant food.' A systematic 

 analysis of localities on all soils with their varying circumstances, 

 soon proves to the critical observer, that whether one of these 

 conditions acts alone, or both together, the}' are not the priniary 

 cause of the selection and combination of species found on tilth 

 or broken ground of any kind. A very little observation, pro- 

 perly directed, will soon convince any unprejudiced mind, that 

 freedom from competition is the chief influencing cause of the 

 appearance of annuals and biennials on freshly moved soils. !t 

 settles the question of the duration of their stay ; and e\ ery- 

 where, under natural and artificial conditions alike, freedom 

 from competition is the most potent influence in the distribution 

 of tranitory species. 



A garden or arable field may possess both the conditions 

 named, but man}' ' cleared spots ' or ' fallow ground ' are 

 wanting in both. Vet, annuals and biennials soon flourish ; 

 and when the soil is deep and rich, are quickly followed by the 

 more persistent perennials. The ' floor ' of a sandy-gravf'l pit 

 has 'the disturbance of the ground,' but as certainly lacks 

 'the imnatural supply of plant food.' Vet, such a pit, within 

 200 yards of my study table, used within the last few weeks, 

 demonstrates the fact that annuals, despite adverse circum- 

 stances, at once take possession of an}' vacant opening. An 



Naturalist, 



