154 
Journal of Agricultural Research 
Vol. XXI, No. 3 
manganese content of the soil. Dementjew (4) discusses the question of 
whether chloroses corrected by iron are really cases of iron hunger. 
The literature on the chlorosis of conifers is relatively small. Sorauer 
(23) has reported chlorosis in Thuja occidentalis in Europe, and Schmuzi- 
ger (21) and Dafert and Kornauth (3) have noted chlorosis in spruce, 
without attempting to connect it with causal factors. Schmuziger re¬ 
ports, as do other observers on angiosperms, that the chlorotic leaves con¬ 
tained plastids which became green when the leaves recovered. Neger 
(16) has described in more detail a chlorosis of spruce in a cold autumn 
in which the yellow leaves or parts of them were found to contain much 
more starch than the green leaves or their green bases with yellow tips. 
He rather vaguely connects both current low temperature and the drouth 
of the preceding winter with the various phenomena observed. 
Contejean (1) lists Scotch pine {Pinus sylvestris) as somewhat calcifuge, 
and makes the general statement that excess lime accompanied by lack 
of iron, or “encore plus” lack of potassium, results in chlorosis of calcifuge 
plants. He, however, makes no specific mention of chlorosis in any 
conifer. Fliche and Grandeau (5) attribute the calcifuge tendencies of 
P. sylvestris to the physical rather than the chemical qualities of lime 
soils. They find Austrian pine (P. austriaca ), P. halepensis , and Abies 
pectinata doing well on strongly calcareous soils, but they find P. pinaster 
making a poor growth in plantations on calcareous soil in all cases ob¬ 
served and entirely refusing to grow in some cases. Deficiency in starch 
and chlorophyll are noted for this pine on the lime soils, and also to a 
very slight extent for the Austrian pine on soils with extremely high 
calcium-carbonate content. The chloroplasts of the chlorotic plants are 
said to be small. The poor condition is attributed to potash hunger, 
and no mention is made of iron hunger as a possible cause. Ash analyses 
showed the following conditions: 
On good soil, 
Pinus pinaster , potash 16 per cent, iron oxid 3.8 per cent, lime 
40 per cent. 
On excessively calcareous soil, 
Pinus pinaster , potash 5 per cent, iron oxid 2.1 per cent, lime 
56 per cent. 
Pinus austriaca , potash 14 per cent, iron oxid 3.3 per cent, 
lime 49 per cent. 
Sachs (20) reports chlorosis in young trees of Abies balsamea, A. 
apollonis t and A . bicolor and says that entirely chlorotic new growth 
becomes green more or less promptly after considerable quantities of 
solid iron sulphate are placed in ditches in the soil near the roots. No 
controls are mentioned, but the promptness with which the younger 
trees are reported to have responded to the treatment supports his con¬ 
clusion that the recovery was due to the iron added, despite the fact 
that fast-growing chlorotic shoots, according to his own statement, 
