PROPAGATION. 



67 



i;hem under atmospheric conditions suoli as would 

 fulfil the same purpose. So soon as absorption takes' 

 place, germination will or ought to commence. Old 

 seeds or immature ones wiU ofterC fail to grow if 

 iept very moist, hut may he induced to push into 

 activity hy keeping them comparatively dry till 

 germination has commenced, increasing the amount 

 of moisture as growth continues. " When the vitiil 

 energies of a seed are diminished, it does not lose its 

 power of ahsorhing water, Tjut is less capable of 

 decomposing it. The consequence of this is that the 

 free water introduced into the system collects in the- 

 <;avities of the seed and produces putrefaction ; the 

 sig-n of which is the rotting of seeds in the ground." 



At Kew, where ail kinds of seeds are received in 

 large quantities annually, it is the custom to treat 

 •old or sickly-looking seeds as follows: — The seeds 

 are first thoroughly dried, so as to destroy any germs 

 •of decay or disease of any kind which may have 

 attacked the seeds before their arrival. They are 

 then spread out thinly upon slates, placed in a warm 

 and moist atmosphere, and covered with a sheet of 

 j)aper. If vitality has not been destroyed, this 

 treatment generally brings about germination, on 

 the first sign of which the seeds are placed in soil. 

 Any health}' seed will germinate if immersed in 

 Tvater of the required temperature, but unless the 

 plant be an aquatic the excess of water soon proves 

 fatal. For all seeds of terrestrial plants, therefore, 

 no more moisture should be allowed than is sufficient 

 to keep the medium on which the seeds are sown in 

 •a moist condition. An excellent guide to follow is 

 that of the plants to which the seeds belong, giving 

 t.heir seeds the same amount of moisture as would be 

 enjoyed by the plants themselves. 



In the case of very fine seeds which are sown on 

 "the top of the soil, it is wise either to stand the pots 

 containing the seeds in shallow pans of water, so 

 that the soil may be kept moist by capillary attrac- 

 tion, or to effect the same purpose by dipping the 

 pots almost up to the rim in water, and holding them 

 there for a few moments till the soil has become 

 t;horoughly moistened. The length of time seeds 

 may be allowed to remain in water without injury 

 ■depends on the nature of their outer coverings. 

 Mr. Darwin made numerous experiments for the 

 ^purpose of discovering how long the seeds of land 

 plants might be immersed in sea-water without 

 losing the power to germinate. He found in many 

 instances the time was unusually long, some of the 

 ■seeds thus tested germinating after an immersion 

 •of 137 days. In like manner many seeds may be 

 kept in fresh water for a long time, if the tempe- 

 rature is not high enough to excite germination 



It is qu:'.te a common practice with gardeners to 

 isteep hard-coated seeds in warm water for a, few 



hours before sowing, the effect of which is the 

 softening of the seed-coats and the excitement of 

 the vital principle, so that germination is much 

 quickened. Peas, Beans, Erythrinas, Acacias, in 

 fact all those seeds belonging to Leguiiunoace may be 

 thus treated before sowing. The effects of soaking 

 in warm water are sometimes of a startling character. 

 At Kew, some time ago, a number of large seeds of 

 various kinds were examined after having been 

 sown in a warm house for over a year, and were 

 found to be quite intact, but showed no signs of 

 germination. They were then placed in water 

 heated to 160", and allowed to remain in soak for 

 twenty-four hours, after which they were re-so^svn. 

 In less than a fortnight after this most of the seeds 

 had begun to germinate, and nearly every seed 

 eventually grew and formed a strong plant. In 

 the same establishment large numbers of Brazil- 

 nuts, Sapucayo-nuts, and other lai-ge hard-coated 

 seeds are annually so^wn, and it is found that by 

 carefully remo^ving the shells before sowing, germi- 

 nation takes place much more speedily than when 

 they are allowed to remain. The same plan is often 

 had recourse to in the treatment of seeds of Olives, 

 Conifera, &c. 



Aquatic plants, such as Nymphasas, Victoria, 

 Euryale, the Buckbean, &c., naturally shed their 

 seeds in water, where they remain dormant as long 

 as the temperature of the water is low, germinating 

 freely and developing into plants on the return of a 

 higher temperature. Although it appears to be 

 nature's plan to preserve these seeds in water, yet 

 they may be kept for a long time in a perfectly dry 

 condition without losing their vitality. Seeds of 

 Nelumbium have been known to germinate after 

 having been kept dry for over one hundred years. 



These seeds may be kept equally well in water if 

 the temperature is not allowed to approach that 

 which induces germination. There are instances 

 recorded of seeds which had commenced to grow 

 having been dried again, and which, on being 

 replaced in a moist situation, grew freely without 

 Buffering materially from the check. But these are 

 exceptional cases, and by no means such as need bo 

 regarded as of horticultural importance. There can 

 be no doubt that when once germination has begun, 

 any check to its progress is as likely to prove fatal 

 as it would be in the case of eggs after incubation 

 had commenced. All seeds, therefore, should be kept 

 dry and in a low temperature till- required for 

 sowing, and when once wetted, no check in the 

 shape of drought or low temperature should be 

 permitted, for even if such check do not prove fatal, 

 it. cannot but prove highly injurious to an organism 

 of such extreme delicacy aa a germinating seed or 

 seedling. 



