INTRODUCTION AND METHODS. 9 



may be variously split to increase the attractive surface. In the interior 

 of the flower any or all of the stamens, staminodes, or pistils may be removed 

 or modified, one or more of the nectaries excised or otherwise changed, and 

 the protective hairs of various sorts trimmed or cut as desired. All vexillary 

 organs external to the flower may be treated in the same manner as petals. 

 Decisive changes in form may be effected by bringing petals together or 

 turning them back, or by treating them to produce an artificial zygomorphy, 

 while the internal arrangement of the flower may be modified by changing 

 the position of stamens, staminode, style, scales, etc. It is obvious that 

 the nectar may be completely removed and the odor also modified in various 

 ways. Two or more mutilations may be combined in the same flower or 

 progressive mutilation may be carried out in a series, ranging from normal 

 flowers through those with more and more parts removed until the pedicel 

 alone is left. Finally, mutilation may be applied to the guide lines, stripes, 

 grooves, etc., but these are usually best modified by masking them with 

 water-colors. 



Artificial and painted flowers. — Between the purely artificial flower 

 at one end of the series and the painted natural flower at the other lie many 

 forms, which differ chiefly in the degree to which artificial or foreign 

 materials are used. Artificial flowers proper may be made of paper, cloth, 

 wax, or other materials, and may be either crude or accurate copies of 

 natural flowers, according to the purpose intended. Plateau has raised 

 many objections to those used by his critics (p. 163), but these seem to have 

 little weight (p. 239). Flowers with one or more artificial parts are termed 

 composites and usually consist of the natural center of a flower or head 

 supplied with artificial petals or rays. In some cases the entire flower 

 or head is used and accessory colored parts added. Artificial stamens, 

 staminodes, or pistils may be added in special cases to replace the natural 

 ones, but such uses are limited. Imitations may be made of green leaves, 

 with or without natural centers, and they are also fashioned by using the 

 centers or disks of one species with the petals or rays of another. One 

 modification of particular value consists in replacing the nectaries or anthers 

 of one species with those of another. The best results have been obtained 

 with natural flowers painted with water-colors, since these are artificial 

 only in color. Such paints may also be employed to mask stripes and spots 

 or to supply new markings to test the directive value of the guide lines. 

 In certain cases natural flowers may be killed by the vapors of osmic acid 

 or otherwise, or they may be used in the dried form when the petals or rays 

 are papery in texture. Bits of colored paper or cloth, or detached petals, 

 have something of the value of artificial flowers, but belong properly in 

 the category of colored objects that can be employed to test color vision. 



Addition of parts or substances. — Additional parts, such as petals, 

 rays, stamens, etc., may be supplied from flowers of the same species or 

 from those of different species. Perhaps the most interesting change of 

 this kind is where the number of nectaries is doubled, and especially when 

 those of another species are alternated. In flowers where the nectar 

 accumulates in considerable amounts in tube or spur, it may be withdrawn 

 and exchanged with that of a different species. Pollen may similarly be 



