472 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



limited to one farm. They grew in a swale which crossed several 

 of the farms, yet were nearly all on one man's property. On his 

 farm they went right up to the fences and stopped, and this could 

 be demonstrated at either side of his property. Unlike his neighbors, 

 he had kept the swale heavily pastured. His cattle had held in check 

 the grasses which are serious competitors of swamp irises. They had 

 also, tramping about in wet weather, turned the swale into more of 

 a quagmire than existed on any of the neighboring farms. They had 

 at length produced an open environment in which the pasture grasses 

 were at a disadvantage and the resulting hybrid swarm of irises at a 

 very real advantage. Hybrids in various patterns of terra cotta, 

 wine, purple, and blue flooded out into this swale until it had almost 

 the appearance of an intentionally created iris garden. 



Though Kiley never published the sequel, it might be inserted here, 

 parenthetically, since it points up some kind of a moral. The farmer 

 himself did not remove the irises, even though they interfered seriously 

 with the carrying capacity of his pasture. The irises were con- 

 spicuously beautiful, and garden-club members from New Orleans 

 dug them up for their gardens, at so much per basket, until they 

 were eventually exterminated. The hybridization that nature began 

 in this and other pastures around New Orleans has been continued 

 by iris fans. These Louisiana irises are now established as cultivated 

 plants both in Europe and in America. Until the arrival of the 

 garden-club ladies, they were nascent weeds (fig. 5) . 



A little reflective observation will show that the ways in which man 

 creates new and open habitats, though various, can mostly be grouped 

 under a few headings: (1) Dumps and other high-nitrogen areas; (2) 

 pathways; (3) open soil; (4) burns. The last is probably the oldest 

 of his violent upsettings of the natural order of things. It must have 

 stimulated evolutionary activity very early — whole floras or certainly 

 whole associations must have come to a new adjustment with it here 

 and there ; fire should be, of all man's effects upon evolution, the most 

 difficult to analyze. Until valid experimental and exact historical 

 methods deal with this problem, it inevitably must spawn more polemic 

 activity than scientific analysis. 



In contrast to fire, the creation of open-soil habitats as a really 

 major human activity belongs much more to the age of agriculture and 

 industry than to prehistory. It may be that is why it seems to be the 

 simplest to analyze. In Europe and eastern North America, in the 

 humid Tropics and sub-Tropics, open soil — bare exposed earth — is 

 scarcely part of the normal nature of things. Most of the flora truly 

 native to these areas cannot germinate in open soil or, having germi- 

 nated, cannot thrive to maturity. Make a series of seed collections 

 from wild flowers and forest trees and plant them in your garden just 



