14 RELATION OF LIME AND MAGNESIA TO PLANT GROWTH. 
In the sea water, therefore, we find a proportion of lime to magnesia 
of approximately 1:3.8, a ratio which would prove injurious for many 
land plants in water culture. The marine plants, such as diatoms and 
fucoids, which in all probability require lime for building up certain 
of their organized structures, must then have means of accumulating 
lime compounds in order to counteract an injurious influence of the 
magnesium compounds entering their cells. Indeed, the ashes of 
marine alge show more lime than magnesia, as seen from the following:! 
Percentage of lime and magnesia in marine plants. 
Marine plants. peat rercent. | 
nesia. 
MUCUS VieSICUOSUISIES os tens Saye eee neh ee a ae ee oe eee be 7 fail 
Hucus MOGOSUS 2-222 425-— She eA een ee Sen ves ea aee SEG ME  T Ad 12.8 10.9 
PUCUS SCIla@GUs ire ease ee eee SoS ae ee eee) See eee a 16.3 Gon 
lamina ria disitata a saaseeee eee oe ese see eee ee ee 11.8 7.4 | 
It is well known that a high lime content of the soil favors some 
plant species more than others, and may even injure certain plants, as 
the yellow lupin. According to Heinrich,’ a soil containing 0.46 per 
cent carbonate of lime will injure the lupin, while 0.5 per cent car- 
bonate of magnesia will prevent its development entirely. Hilgard 
mentions for the southern part of the United States the linden tree 
wild plum tree, and the tulip tree (Liriodendron) as indicative of a 
soil rich in lime.’ On the other hand, the southern pines and certain 
kinds of oak and Vaccinium are indicative of a lack of lime in the soil.‘ 
With certain other plants some variations in growth depend on the 
abundance or deficiency of lime in the soil, as Hilgard has pointed out 
for Quercus ferruginea and (Y. obtusiloba. This author has also called 
attention to the lower growth but richer yield in seeds and fruits on 
soils with a high lime content. But, on the other hand, a deficiency of 
lime may also reduce the size of certain organs. Thus the leaves of 
young pine trees reach only half the normal length when lime salts 
are deficient, as Honda and the writer have observed.’ 
It is a natural and logical conclusion that an analysis of soil properly 
made with regard to the absorbing capacities of the plant roots must 
1Gédechens, Ann. Chim. Pharm., 1854, Vol. LIV. 
Some marine alge, such as certain members of the Floridez, exert a powerful 
attraction upon the lime salts (by probably containing certain organic acids yielding 
insoluble lime salts), depositing much calcium carbonate in the cell walls. 
* Jahresber., f. Agr. Chem., 1896, p. 239. 
’In Europe Gentiana ciliata is one of the characteristic lime-soil plants. 
*The coast pine (Strand Kiefer) can grow in Europe only on soil poor in lime 
(Grandeau and Fliche, 1878). 
> Bull. College of Agr., Tokyo, Vol. II, No. 8. 
