260 BOTANICAL GAZETTE [SEPTEMBER 
Haas” on this question. Determination of the total acidity and actual 
acidity by means of titration, and the gas chain and buffer solutions, shows that 
the reaction of the cells studied ranges from about Pa+3 to Pa+7. If we 
call the buffer solution acid up to Pa+7, neutral when at Pz+7, and alkaline 
when higher than Pu+7, it is evident that it is unsafe to call cell sap acid when 
- red, neutral or alkaline when blue, and markedly alkaline when green, unless 
the color changes of the particular pigment are first studied by some method, 
such as that of using buffer solutions of known hydrogen ion concentration. 
One other study may also be mentioned in this connection. These chem- 
ical investigations inspired a study by Sarpata, Nacat, and Kisuma*™ of 
the physiological and biological significance of the anthocyans and flavones in 
plants. The evidence: obtained established a somewhat unexpected fact, 
namely, that the flavone derivatives are one of the cell contents of very com- 
mon occurrence in the plant kingdom. In fact, they are quite as common as 
chlorophyll, tannins, sugars, starches, and proteins. They are not only found 
ae He yebow Dosing wiatter, but also in the cell sap of the epidermis and in 
the underlying tissu general jal: eal the 
lete ab f chr for example, in the white corn flower 
: (Centaurea cyanus), oxalis (Oxalis violacea), pink (Dianthus caryphyllus), and 
(Pelargonium cucullatum). The function of the flavone deriva- 
tives dissolved in the cell sap is to protect the living protoplasm and the 
important biochemical agents involved from the injurious action of the ultra- 
violet rays of sunlight by absorbing them at the peripheral layer of the plant 
ihe plausibility of this assumption is justified by an extensive 
study of th The green leaves of deciduous 
trees, which produce anthocyan pigments in autumn, contain a co considerable 
amount of flavones. The production of autumnal color is due to the bio 
chemical change, that is, the red flavones in the leaf, 
initiated by the physiological condition at the end of the growing season, with- 
out having special ecological significance. 
This brief survey of recent progress in anthocyan chemistry makes it seem 
very probable: that i in the near future we may have a complete 
based up dd f the chemical 
. ‘arachos @ tad akieip ee aa Tt ie to be boped that the work say ee 
any GEREN ea oe ee West. 
"Taxonomic notes Evans” ‘has ‘published a monog! aph of the North 
- 
6 : bedi of Jama) sno. bolas = ten: — esc ae ue 
of Marchantia, recognizing 9 aes one of which (M.— 
