4 BULLETIN 600, U. S. DEPARTMENT OF AGRICULTURE. 
TITANIUM. 
According to Salm-Horstmar,: titanium may exist in the ash of 
barley and oats. 
VANADIUM. 
Bechi? found vanadium in various plants, especially those growing 
on clay soils. It was present in grasses growing on Etna lava in 
quantities too small to estimate. Its occurrence in plants is regarded 
as being due to its ismorphism with phosphoric acid. Coals from 
Belgium and Peru have been found to contain vanadium. Demar- 
cay * detected traces of vanadium in vines, fir, poplar, and hornbeam. 
Ramirez * states that vanadium is absorbed and stored by some plants 
and causes anomalies in their growth. 
ZIRCONIUM AND RARE EARTHS. 
No mention is made of the occurrence of these elements in plant 
ash. Three plants only were tested for zirconium and the rare earths 
in this work. 5 
SELECTION AND PREPARATION OF THE SAMPLES. 
So far as it was practicable, the plants selected for this work had 
grown on soil that previously had been analyzed in these laboratories, 
and the plant samples were taken as near as possible to the spot where 
the soil sample had been taken. In selecting plants consideration was 
given to the fact that there are variations in the composition at dif- 
ferent stages of growth and also to the fact that rain water falling 
on growing plants leaches out no inconsiderable amount of soluble 
inorganic plant constituents and returns them to the soil. The plants 
were selected with as much uniformity as possible, the aim being to 
gather them when in bloom. Im all cases, except when otherwise 
stated, the entire part of the plant above ground was taken for 
analysis. The majority of the samples were gathered during’ the 
latter part of June, 1915. Important crop plants would have been 
preferred to some of the trees and waste-land grasses, but some soils 
that had previously been analyzed did not support such crops, so 
trees and weedlike plants were used. In beginning the investigation 
it was hoped to study the composition of the same kind of plants 
grown on soils differing widely in composition; for instance, to com- 
pare the lime content of red clover grown on a Hagerstown loam hav- 
ing 0.93 per cent CaO with red clover grown on a York silt loam 
having 0.08 per cent CaO. No legumes whatever could be found 
growing on the latter soil, a fact which in itself is significant. 
1 Johnson, ‘‘ How Crops Grow,” p. 137. New York (1890), Orange Judd Co. 
2 Atti. Accad. Lincei (3) (Mem. Sci. Fis. Mat. e Nat.) 3, 403 (1878-79). 
3 Loc. cit. 
«Anales. Soc. Quim., Argentina (2), 6, 145 (1914). 
