THE GARDENER. 



35 



of the earth. It is said as a standard of density, that 

 this need not exceed the bulk of the individual grain; 

 but much more may generally be applied, if it were 

 only from the necessity of guarding against the attacks 

 of bu'ds. For small seeds the earth ought to be very 

 fine, and for some sorts sand or peat mould lightly 

 scattered over them is the only covering they can 

 bear, without the young plant suffering in its ascent 

 from the loss of light and heat.* Other grains, on 

 the contrary, can support a heavy coat of argillaceous 

 earth without inconvenience.- Experience must be 

 your guide in these particulars. 



But seed is in numerous cases unfertile altogether: 

 the finest varieties of fruits^ all the double flowers so 

 prized, are more frequently sterile than fertile from the 

 following causes — viz. the absorption by some near 

 member of the plant of organic matter which is essen- 

 tial to the perfection of the grain. Sometimes portions 

 of the plant distant from its fruit are so constructed, 

 that they attract to themselves the nourishment de- 

 stined for the fruit, and thus present an obstacle to 

 the development of seed. The early varieties of the 

 potatoe, for example, cannot easily yield seed, because 

 their tubers absorb the nutritive matter necessary for 

 the development of the seed. Some of the most deli- 

 cate varieties of the pear seldom produce seed from 

 this probable cause, according to Professor Lindley. 



* " As far as general rules can be given on such a subject, it 

 may be laid down, that the temperature of the earth most favour- 

 able for germination, is from fifty to fifty-five degrees for seeds 

 of cold countries, from sixty to sixty-five degrees for those of 

 plants requiring moderate stove-heat, and from seventy to eighty 

 degrees for those of the torrid zone." — Professor Lindley, By 

 boiling seeds, those of the Acacia Lophanta for instance, the 

 germination may be assisted partly, as the Professor observes, by 

 the mechanical effect of the heat, in causing the shells to burst, 

 and partly by dissolving and stimulating the substances they 

 contain. 



