72 Commercial Gardening 



possible from those of a similar nature, to prevent the pollen being carried 

 from one to the other. 



Seeds vary considerably in size, from almost dust-like grains to that 

 of Peas, Beans, Acorns, and upwards, to Coconuts. They are borne either 

 singly or severally in their pods or ovaries, some plants like Begonias, 

 Poppies, Marrows, &c., having from 300 to 600 seeds or more in a pod, 

 while there are several thousands in many orchids. Whatever the size 

 may be, each seed is the result of an ovule having been fertilized by the 

 contents of the pollen tube that penetrated the tissues of the pistil from 

 the stigma downwards, as the result of the pollen grains germinating. In 

 the case of Fern spores which are popularly known as " seeds " the process 

 is quite different, and is explained in the article on Ferns in Vol. II. 



Each seed, when thoroughly ripe, contains sufficient nourishment to 

 start the young plantlet in life under favourable conditions, and the main 

 object of the cultivator is to get the seed-leaves up to the light as soon 

 as possible, so that they may be able to assimilate the carbonic acid gas 

 from the atmosphere to develop further tissue. Some seeds germinate 

 more quickly than others, and seeds of the same plant will germinate 

 either quickly or slowly according as it is in a favourable temperature 

 or not. Under the best conditions some seeds take a long time to 



o 



germinate, often owing to the extreme hardness and thickness of their 

 coats. Experience has proved, however, that hard -coated seeds will 

 germinate readily as soon as they drop from the parent plant; but if kept 

 for a few months, and then sown, a considerable time may elapse before 

 they begin to sprout. For this reason seeds of Cannas, Nelumbiums, and 

 many of the Leguminosae are often filed before being sown, to reduce the 

 thickness of the hard bony coat surrounding the embryo plant within. 

 It may be worth while to quote the following remarks of the late Herr 

 Max Leichtlin, from the Gardener's Assistant: "If practicable, it would 

 be best to sow all seeds of hardy plants at once when ripe; we only delay 

 sowing for the sake of convenience, because we should, in the case of 

 autumnal sowings, be obliged to house a very large number of pans and 

 boxes of young plants too small to pass the winter outside. Hard-shelled 

 seeds must be sown at once, also all seeds of hardy bulbous plants. If 

 seeds of Colchicum be exposed to the air for a few days, not more than 

 5 per cent come up within a year, and the rest may take five years to 

 germinate, whereas, sown as soon as the seed pod splits, 30 per cent will 

 germinate in the first year. Delay sowing the seeds of Lilium, Fritillaria, 

 Tulipa, &c., and you will lose from 20 to 80 per cent. Campanulas 

 and Ostrowskya readily germinate when sown at once, but if sowing is 

 deferred till spring the seeds will probably lie dormant for a year, if they 

 do not perish altogether." 



The following data as to the number of days taken by various seeds 

 to germinate may be of interest. The night temperature was about 60 F., 

 and the day temperature ranged from 65 to 70 F. Those marked with 

 an asterisk (*"> were sown in the open air. 



