332 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



the petiole-end into the leaf blade (pi. 7, fig. 28) . This variegated con- 

 dition ordinarily is quite stable. However, figure 28 illustrates a plant 

 that has a completely green branch and one that is chlorophyll de- 

 ficient, in addition to branches that have typically variegated leaves. 

 Cuttings from the green branch will reproduce vegetatively, continu- 

 ing to be green and presumably like the parent of this variegated 

 variety. Cuttings from the mutant yellow-green branch will root and 

 continue to grow with all new leaves and branches having the chloro- 

 phyll-deficient color. It is less vigorous and more care is necessary in 

 keeping conditions right for growth. 



The above two geraniums (Silver Leaf S. A. Nutt and Mme. Sol- 

 leroi) illustrate how mutations occurring in vegetative parts may 

 result in chimaeras. The mutation may have occurred but once many 

 years ago, for each variety, and the mutant chimaeral or variegated 

 state has been maintained by vegetative multiplication. Most varie- 

 gated plant varieties may be used to demonstrate a mutant individual. 

 The exceptions are found in some varieties that have genetic patterns 

 characteristic of some Goleus varieties, and albino spots, blotches, or 

 streaks due to viruses, as in Ahutilon pictwn (flowering maple) . The 

 geranium specimens illustrated in figures 28 and 29 (pi. 7) demon- 

 strate vegetative or somatic segregation of the mutant tissue from the 

 chimaera as well as segregation of the original type — the green 

 branches. Obviously meiosis is not involved in this segregation, but 

 is due to fortuitous anatomical deviations. For centuries man has been 

 taking advantage of these vegetative or somatic segregates ("sports" 

 of the older horticultural literature) without much of an understand- 

 ing or appreciation of how they came about. It has been of great im- 

 portance in obtaining new and useful plant varieties not only among 

 ornamentals, but in most modern varieties of apples, pears, grape- 

 fruits, oranges, peaches, grapes, and many others. 



An unnamed variegated Coleus variety, with leaves characterized 

 by a dark-red backgi'ound with flecks of yellow distributed without 

 any particular order or constant pattern, was maintained in culture for 

 several years. From one plant a branch developed which bore com- 

 pletely red leaves (pi. 8, fig. 30) . Cuttings from this branch have con- 

 tinued to be dark red in color without any indication of yellow flecks. 

 Figure 31 (pi. 8) is a photograph of a plant of the same variety ex- 

 hibiting a yellow-leafed branch. The yellow branch propagated vege- 

 tatively, and continued to be entirely yellow with the characteristics of 

 the commercial Golden Bedder variety. A third mutation was ob- 

 served from the same unnamed variety and is illustrated by figure 32 

 (pi. 8) . The mutant branch bore leaves which were red with a yellow 

 border around the edge of the leaf blade. Several similar mutations 

 resulting in chimaeras have been found in Coleus. 



