CHLOROPHYLL 311 



before they are set free from the ovary or from the cone ; 

 Pinus, Euonymus europcsus, and species of Ciicurbita are 

 famiUar examples. In some of these cases Hght no doubt 

 does penetrate through the walls of the superposed cells ; 

 this may be well seen if the seeds be removed and the lumen 

 of the fruit of the vegetable marrow be cleaned out. It is 

 hardly necessary to remark that if the chlorophyll in these 

 deeply-seated tissues be functional, its contributions to the 

 food-stuffs of the plant, as Goldfius * has pointed out, must be 

 of considerable value. 



But in some cases the pigments of such chloroplasts may 

 not be the same as those of the ordinary chloroplasts of the 

 leaf ; thus, according to Monteverde and Lubimenko,t the 

 seeds of many Cucurbitaceae contain not chlorophyll, as ordin- 

 arily understood, but chlorophyllogen,J which may pass over 

 into chlorophyll under the influence of light and some other 

 factor, possibly enzymic. 



Also it must be remembered that it does not follow that 

 because chlorophyll is present, photosynthesis necessarily takes 

 place, even though the requisite conditions, light and supply 

 of raw material, obtain. Thus it appears probable that the 

 chlorophyll in green parasites is not functional, and the same 

 holds for the chlorophyll in the gyngecium of certain plants, 

 e.g. Oniithogalmn arabicum. At any rate, in these cases the 

 photosynthetic power is so small as to be masked by the 

 respiratory activity. 



Attention may here be drawn to the work of d'Arbamont § 

 who considers that the plastids containing chlorophyll may be 

 divided into two classes, chloroplasts and pseudochloroplasts. 

 Of these the former include those bodies usually termed chloro- 

 plasts, and are characterized by the fact that they do not swell 

 in water, and do not, as a rule, stain when treated with acid 

 aniline blue. On the other hand, pseudochloroplasts swell in 

 water and do stain with aniline blue. In some cases plants 

 may contain pseudochloroplasts only.|| 



* Goldfius : " Rev. Gen. Bot.," 1901, 13, 49. 



t Monteverde and Lubimenko : " Bull. Jard. Imp. Bot. St. Peters- 

 bourg," 1909, 9, 27. X Later described as Leucophyll. 



§ D'Arbamont : " Ann. Sci. Nat. Bot.," 1909, 9, 197. 

 II See Belzung : id., 1891, 13, 17 ; " Journ. Bot.," 1895, 9, 67, 102. 



