BY W M. CARNE. 851 



An average sample of the soil at Grose Vale has been found, 

 by Mr. M. S. Benjamin, Assistant Chemist, Hawkesbury Agri- 

 cultural College, to contain 4-23% of lime. The litmus reaction 

 is faintly alkaline. Round the outcrop, owing to the inter- 

 mingling of the shale with the limestone, and the leaching of the 

 latter, the amount of lime is much smaller, less than 05%. 

 Here the two floras tend to mingle to some extent, although the 

 boundaries of the two are remarkably distinct. Here, too, are 

 found some plants, marked (J) in the accompanying list, which, 

 while not occurring on the limestone proper, are hardly typical 

 of the Wianamatta proper. These may be almost classed as an 

 intermediate flora. It may be mentioned that Wianamatta soils 

 give a strongly acid litmus reaction, and an average analysis of 

 ten samples shows only 0"136/o of lime.* Where, as in Australia, 

 soils tend to be deficient in lime, the amount present is often, to 

 a large extent, indicative of the value of the soil to plants. f It 

 is recognised in agriculture that the value of lime in a soil lies, 

 not so much in itself directly, as in the part it plays in encouraging 

 bacterial action, in rendering soil-foods available to plants, and 

 in improving the texture of the soil. The chief cause of the 

 luxuriant brush-like vegetation under consideration is the rich 

 open soil, resulting from the presence of an unusual amount of 

 lime. The difference in the vegetation on acid and basic granites, 

 as pointed out by Mr. Cambage and others, is due to the same 

 reason, for " acid granites low in lime-minerals yield poor soils; 

 basic granites fairly well supplied with lime-minerals yield good 

 soils. ":|: "Although the characteristics of the lime-flora are clear 

 and distinct, yet, in the past, the influence of lime upon vegeta- 

 tion has been overestimated. Indeed, a distinction has been 

 made between calciphilous and calciphobous plants. Recently 

 it has been definitely established that the amount of lime, in 



* Jensen, H. I., Agric. Gazette of New South Wales, 1910, p.463. 

 t Guthrie, F. B., Agric. Gazette of New South Wales, 1898, p. 484; and 

 Jensen, H. I., op. cit. 1909, p.l091. 



X Jensen, H. I., Agric. Gazette of New South Wales, 1910, p. 105. 



