678 



well as of white coloring. Among these, the calla, frequently cultivated in 

 the house {Zantedeschia aethiopica), shows leaves which often are as pure 

 white as the funnel-shaped blossom sheath. The bright colored calladia, 

 greenhouse favorites, are related to the Zantedeschia. Among them a few 

 are only specked with white, others have white and red spots, and many 

 finally only red spots. 



The white spotted condition of the flowers and the more rare albinism 

 of fruit are difficult to distinguish. Of the latter, Dufour^ has described 

 interesting cases in grapes. 



There prevails, especially in practical circles, an earnest hesitation in 

 accepting the theory which ascribes the white variegated leaves to the 

 phenomena of disease. Yet, we believe that this opinion must be defended. 

 If we investigate a considerable number of plants with variegated leaves, 

 we find all gradations in the cells from the normal chloroplasts to the entire 

 disappearance of the chloroplastids. The parts of the plants which appear 

 yellowish often have chloroplasts which appear as yellow, sponge-like balls 

 or discs in the cells ; the purer white the plants are, the fewer are the even 

 colorless chlorophyll bodies ; and the more the cytoplasm assumes the ap- 

 pearance of a soft, uniform wall lining. The intercellular spaces contain 

 more air and at times are larger. 



The assimilation of carbon dioxid also ceases with the disappearance 

 of the chloroplasts. Cloez- and later Engelmann^ found that the leaves 

 assimilate carbon dioxid only in proportion to their chlorophyll content. 

 The diiiferent gradations in the yellow variegation arise from lesser quanti- 

 ties of the same chlorophylline and zanthophyll, than occur in the normal 

 green leaves* and their assimilator}' activity is in accordance with this. 



In pure white leaves the chlorophyll does not form and the chloroplasts 

 are poorly developed. In the yellow forms, chloroplasts are found at least 

 in the bud and often later but the degree of degeneration of the chloroplasts 

 depends on their proximity to the pure white zone. The analyses given by 

 Church^ serve as a good confirmation of this. He used white variegated 

 forms of maple {Acer Negundo), Ivy (Hcdera Helix) and Holly {Ilex 

 a qui folium) : 



1 Defour, J., Panachierte Trauben. Extr. Chronique ag^ric. du canton de Vaud; 

 cit. Zeitschr. f. Pflanzenkrankh. 1904, p. 286. 



2 Compt. rend. LVII, p. 834. 



3 Engelmann, Faibe und Assimilation, Bot. Zeit. 1883, Nos. 1 and 2. 



4 Kranzlin, G., Anatomische und farbstoffanalytische Untersuchungen an 

 panachierten Pflanzen. Inaug.-Diss. Berlin 1908. 



5 Church, Variegated leaves. Gardeners' Chronicle 1877, II, p. 586. 



