NOTES AND ABSTRACTS. 



681 



by stating that the study requires the most careful technical research and 

 seems to have been greatly neglected by plant physiologists and patho- 

 logists. Similar symptoms may develop in the plants from the most 

 diverse causes. All the conditions of environment and hereditary 

 tendencies must be known. The kind and quantity of food is a prolific 

 source of variation, for a plant grown on a rather poor soil compared with 

 one grown on a very rich soil might not at first be recognised as the same. 

 Plants of course obtain their nitrogen from nitrates in the soil, and are 

 not able to absorb it from the air. 



The following table is given of the analysis of the Clover plant, showing 

 the percentage of the elements : 



From 70 to 90 per cent, of the weight of living plants is water. 



In many cases it requires very careful watching to prevent starvation 

 and stunting in light soils. These conditions, however, favour some crops, 

 like Sweet Potato and Peach. The ideal condition of a soil for ordinary 

 field and greenhouse crops is one in which it resembles a sponge, and in 

 which it will retain the greatest amount of nutritive substances and water 

 without losing its capacity of absorbing air. The greatest dangers due 

 to unsuitable mechanical conditions of soils are poor drainage and 

 consequent excess of water and lack of oxygen. Plants, especially trees 

 growing where the surface soil becomes caked and packed, are likely to 

 suffer for want of oxygen for the roots. 



The soil foods necessary to plant growth are fully explained under 

 the following heads : Influence of magnesium and lime ; function of 

 calcium in the soil ; importance of potassium ; is chlorine a food ? 

 function of phosphoric acid ; nitrogen as a constituent, and its effect 

 on growth. 



The question of excess of food in solution is discussed. If the solid 

 matter in solution in a soil exceeds 1 part in 500 parts of water, it is 

 bearing a limit beyond which many plants are likely to suffer ; the leaves 

 turn yellow on the edges, become spotted and drop off, or growth is 

 checked, shortened, and compacted ; the leaves often become puckered and 

 twisted. — V. J. M. 



Nymphaea * George Huster ' (Gard. Mag. No. 2600, p. 578 ; 

 29/8/03). — An illustration with descriptive note of this beautiful new 

 hybrid Water-Lily, said to have been raised from N. stellata (as one 

 parent) by Mr. Dreer of Philadelphia. — W. G. 



Odontoschisma Macounii, and its North American Allies. By 



A. W. Evans (Bot. Gaz. vol. xxxvi. No. 5, p. 321, pis. xviii.-xx.). — These 

 Hepatics were collected in the Yukon Territory, and the author describes 



Carbon 



Oxygen 



Hydrogen 



Nitrogen 



Sulphur 



47-4 

 37'8 

 5-0 

 2-1 

 0-12 

 0-30 

 2-0 



Phosphorus 

 Remaining ash . 



B B 



