SEEDS WEEDS. 767 



Colony, the report being prefaced with an account of the climate, soils, rainfall, and 

 winds of the region and comparisons drawn from other artificial plantations of this 

 species. The tree readily reproduces itself from seed and is well adapted to coppice 

 as well as standard growth. The blue gum was said to have been introduced in 

 Europe probably as early as 1820 and since that time has been brought under culti- 

 vation in a num))er of localities. Tabular reports are given of the total and mean 

 annual growth of this species in a number of regions, the annual increment varying 

 f i-om 273 to (596 cu. ft. per acre. After the general discussion of the subject an account 

 is given of plantings in South Africa, one of which contains 20 acres and was planted 

 at a cost of S.'JO.To per acre. This includes the clearing and preparation of the land, 

 together with the care of the trees until they are about 2 years old. The author esti- 

 mates that plantings conducted at this rate would give a clear profit of about $7 per 

 acre if conducted by the government, or if funds could be borrowed at as low rate as 

 21 per cent, which is readily secured by the government. The growth and acre 

 increments are given, together with the data regarding the planting of 12 plantations 

 whii'h ranged from ,3 to 12 years old. 



"Wood and cork, E. n' Hubert {Le hois el le UPge. Parit: J. B. BaUliire & Sons, 

 1903, jij). 9G, figs. 31). — A description is given of the anatomical, physical, and chem- 

 ical characteristics of various kinds of timber, descriptions of the timber-producing 

 species, the commercial production, conservation, and utilization of forest products, 

 together with statistics of forest production. 



SEEDS— WEEDS. 



The influence of lieat on the germination of seeds, H. H. Dixon ( Gard. Chron., 

 3. ser., 3:2 {1902), Xo. 8.'1, ji. ..'17). — A l)rief account is given of a paper read before 

 tlie botanical section of the British Association, in which the author's experiments 

 on the resistance of seeds to high temperatures are described. As p)relirainary to the 

 experiments the seeds were dried either over sulphuric acid or in ovens, the tempera- 

 ture of which was gradually raised to 90° C. After drying they were exposed for an 

 hour or more to a higher temperature and then sown on moist sand. The seeds of 

 the different varieties showed individual differences in their power of resisting high 

 temperatures. A large percentage of oats would germinate after an exposure of from 

 100 to 105° C, while very few germinated if exposed to temperatures of 118° C. In 

 general the higher the temperature to which the seeds were exposed, the longer 

 would be the period of germination. Long exposure to comparatively low tempera- 

 tures was found to be more fatal than a short exposure to a much higher one. Those 

 seeds which germinated successfully after 1 hour's exposure at temperatures of 110 

 to 120° C, would not germinate at all if exposed for 12 days to temperatures of 95 

 to 97° C. 



The germination of seeds after exposure to high temperatures, H. H. Dixon 

 {Xotes Hot. School, Tfiiiilij Col., Diihliii, 1902, Xo. 5, jqi. IIH-ISG). — In continuation 

 of experiments previously reported (E. >S. K., 13, p. 462), the author has investigated 

 the effect of high temperatures as influencing the germination of seed, and has been 

 able to confirm the results previously obtained. Exjjosure of seed to high tempera- 

 tures retards the germination, prolonging the period for a considerable time. In 

 many cases the germination of seed in the experiments was abnormal, the most 

 frequent abnormality being the protrusion of the cotyledons instead of the radicle 

 from the seed. In manj' instances where the radicle emerged normally it was often 

 abnormal in its suljsetiuent behavior. Although many seeds were found able to 

 withstand high temperatures for a comparatively short period, when subjected to 

 moderately high temperatures for a prolonged time the germination was almost 

 entirely destroyed. 



