ANTHOCYAN TN THE PETALOID CALYX. 15 



protein substance com1)ine<l with some fotty bodies. It is different 

 from oil drops. ^* 



Chloroph3'll-grains increase mncli in the mesophyll and, hitier, 

 starch-grains of large size appear in al)undance ; soon afterward 

 the chlorophyll-grains begin to degenerate. 



Crystals of calcium oxalate decrease remarkably in amount and 

 tend to disajipear. lîaphides, though very few, remain unchanged. 



III. Summary. 



1). When anthocyan has completed its development, chloro- 

 phyll-grains l)egin to appear in the mesophyll layer of the calyx 

 and, at a later period, deposit a large amount of starch-grains. 



2). After the appearance of the red colouration on the upper 

 side, the llower-stalk nutates downward to expose its lower side 

 directly to the sunlight. In this position, the lower side also 

 assumes a reddish tinge. 



o). The flower remains open for about four months in summer, 

 and the calyx-leaf is persistent throughout this period. 



4). Protanthoeyan from which yellow, red, deep red, or 

 bluish anthocyan and also Iduish violet crystals are derived, consists 

 of a certain colourless tannin compound. 



5). Protanthoeyan becomes yellow or green by alkalis. 



6). In the red Hortense, the blue colour appears later than 

 the red, and bluish crystals are often met with within reddish 

 or purple cell-sap. Such variations as is well known depend on 

 the different degrees of acidity. 



7). The essential fiictors which bring about the change of 



1) Kywosch, 8. — Einiges über ein in den grünen Zellen vorkommendes Oel tnid seine 

 Beziehung zur Herbstfärbung des Laubes. (Ber. Peutscli. Bot. Ges. 1807. p. 195). 



