544 



Tin-: Journal of Heredity 



A VARIEGATED COLLECTION 



(a) Abutilon, a i^criclinal chimera whose green leaves have white edges. In the upper leaves 

 the envelopment of the green by the white tissue is not complete. The misshapen leaves 

 show that the outside skin of white tissue exerts a restraining influence on the growth 

 of the normal and more vigorous green tissue, (b) and (c) show other abutilon leaves, 

 spotted but probably as the result of infectious chlorosis because they are certainly not 

 chimeras, (d) is the Wandering Jew {Tradescantia fluniiuensis), a good example of sectorial 

 chimera. It is remarkable for the fact that the guard cells of tlie stomata — the breathing 

 pores of the leaf — always contain green granules of chlorophyll even if situated over 

 white tissue, or on pure white leaves. This is not the case in the variegated jiigwecd or 

 geraniums, (e) Leaf of the Small Mallow {Malva rot nndi folia), a common weed. The 

 light areas are pale green, not white. Some leaves on the plant are wholly dark green 

 while others are wholly light green. It appears to be a sectorial chimera formed partly of 

 pale green "chlorina"-like tissue and partly of normal dark green tissue. Hereditv un- 

 determined. (Fig. 16.) 



lion in the l'\ j^encralion occurs when 

 the pollen of "albomaculata" plants is 

 used on the blossoms of green plants, 

 both the Fi and the Fj plants being 

 green. On the other hand, when the 

 pollen of green plants is used on "albo- 

 maculata" blossoms the result is exactly 

 the same as if the flowers had been self 

 fertilized. 



Correns' theory is that the "albo- 

 maculata" character is due to a disease 

 of the cytoplasm which does not afi'ect 

 the nucleus. The nuclei in these plants 

 are supposed to carry factors necessary 

 for chlorophyll formation like those of 

 nornial green plants. No cytoplasm, 

 however, is carried into the egg cell by 

 thc> male gamete, but onh" nucUvar 



materal. So the condition can only be 

 transmitted by the mother plant and 

 apparently the female cells of the 

 "albomaculata" plants may be affected 

 to a variable extent, or not at all, which 

 accounts for all the facts. 



SEC'TOKI.XL CIII.MI^R.VS. 



Our knowledge of the heredity of 

 white and green leaved chimeras rests 

 largely on Baur's (4) work with geran- 

 iums. vSvich ])lants wnth grayish green 

 leaves with white edges are familiar 

 to every one while the reverse type 

 whose leaves ha\'e white or pale green 

 centers and green edges is only a little 

 less common. In these ])lants. as has 

 been said, the t'mbrxonic tissue in ih 



