464 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



The world's knowledge of crop plants, in other words, does not tell 

 us very much. All we know is that we are dealing with man's effects 

 on certain plants in the Neolithic or before. Yet for weeds and orna- 

 mental plants even less is known. A few general observations may 

 be offered, parenthetically, about their origins. 



1. We can now point to crops that are definitely known to have been 

 derived from weeds. For instance, rye as a crop originated from a 

 grainfield weed (Vavilov, 1926). As barley and wheat spread farther 

 north onto the sandy Baltic plain, the weed gradually replaced the 

 crop. The origin of rye as a weed is a far older and more complex 

 problem. Stebbins and his students are far enough into it to tell us 

 that it is a story with several chapters, most of them unsuspected until 

 recently. 



2. We can point to weeds that originated from crop plants. The 

 bamboo thickets that cover whole mountainsides in the Caribbean 

 came from cultivated bamboos. It now seems much more probable 

 that teosinte the weed was derived from maize the crop than that 

 maize was derived from teosinte. 



3. Crop plants and their related weeds frequently have a continu- 

 ing effect upon each other. We have documented evidence of weeds 

 increasing their variability by hybridizing with crop plants and of 

 crop plants consciously or unconsciously improved through hybridi- 

 zation with weeds. These processes recur repeatedly in the histories of 

 weeds and crop plants. For wheat it is clear that a minor grain was 

 in very early times built up into one of the world's great cereals 

 through the unconscious incorporation of several weeds from its own 

 fields (Anderson, 1952, pp. 57-64). 



As a whole, ornamentals (though little studied as yet) provide the 

 simplest keys and the clearest insights into the basic problems of do- 

 mestication of any class of plants or animals. Some have been do- 

 mesticated within the last century — the African violet, for instance — 

 but are already distinct from the species from which they arose. 

 Such recent domesticates provide unparalleled experimental material 

 for determining what happens to the germ plasm of an organism when 

 it is domesticated. Others of our garden flowers originated in pre- 

 historic times. They seem to have been associated with magic and 

 ceremony ; some of them may have been with us for as long as or even 

 longer than our crop plants. Take woad, Isatis tinctoria, now known 

 only as a garden flower, though it persisted as a commercial dye 

 plant until Victorian times (Hurry, 1930). When Caesar came to 

 Britain, he found our semisavage ancestors using it to paint their 

 bodies. There are various other ornamentals (Bixa, Amaranthus, 

 Helianthus) whose earlier associations were with dyes and body paints. 

 Which is older, agriculture or body painting? 



