28 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



As an indication of the quantities of seeds produced by some weeds, 

 it may be pointed out that a single plant of — 



Charlock 



Shepherd's Purse 



Poppy 



Chickweed 



Cleavers 



Groundsel . 



Perennial Sow Thistle . 



Coltsfoot 



Dandelion 



Scentless Mayweed 



Field Bindweed . 



Narrow-leaved Plantain 



Burdock 



may produce 1,000 — ■ 

 4,500 



4,000 seeds 



60,000 



500 

 1,000 



300— 20,000 

 3,000— 19,000 

 5,000 



3,000— 5,000 

 34,000—310,000 

 600 



2,500— 15,000 

 24.000 



Another point should be briefly noted, viz., that many seeds possess 

 great vitality, and may lie dormant in the soil until conditions are 



1 



IPhoto : H. C. Long, 



Fig. 2. — A Weed-distributing Area : Showing an Abundance of Thistles 

 AND other Weeds in Flower, and a Big Crop of Leaves of Coltsfoot. 

 (Photographed about June on a suburban building plot.) 



favourable for germination, when the plants suddenly appear and cause 

 trouble. Professor Peter has shown that Charlock may lie dormant in 

 the soil for forty years, and it is well known that the seeds of many other 

 plants may survive and germinate after several years, while others even 

 pass unharmed through the digestive tract of live stock and birds. 



The numbers of seeds which may be found in the soil of a garden 

 or field varies considerably. In his own garden the writer found in a 

 square yard of soil (in May 1909) no fewer than 1050 seedhngs (or 



