30° CHELTENHAM COLLEGE NATURAL HISTORY SOCIETY. 
Let us take our English Spotted Orchid with its one hundred and 
eighty six thousand three hundred seeds. 
Each plant occupies about a square of six inches and thus we 
can have 174240 plants in one acre. Now since some seeds are 
sure to be bad and incapable of germinating, let us for convenience 
assume that one plant produces 174240 good and 12060 bad seeds. 
This I think seems a fair supposition. The children of our one 
plant will cover an acre, but the grandchildren must cover 174240 
acres—an area which would occupy most of the Vale of the Severn 
from Gloucester to Worcester and from Cheltenham to Malvern. 
The great-grandchildren further would cover 174240 times the 
space of their immediate parents, or nearly the land of the whole 
globe (47 : 50). 
Now take Acropera, we have children 74 millions, grandchil- 
dren 5,476 billions, great grandchildren upwards of half a trillion 
OF 405,224,000,000,000,000,000,000 plants. 
Allowing the same percentage of bad seeds as in the Spotted 
Orchis, these great-grandchildren would being larger plants suffice 
to cover the land of the whole world twelve million times over. 
From this nothing can be more obvious than that most of the 
seeds produced can never grow to anything. 
A second point is brought forward by the fact that seedlings 
growing too closely kill one another—the stronger starving or shad- 
ing the weaker: hence zt zs to the benefit of a plant to scatter its 
seeds widely. ‘Thus in our Spotted Orchis, for the progeny of one 
individual to cover an acre, some of the seeds must travel to a 
distance of 25 yards. Similarly requirements must act in other 
plants, and it is this which produces the following main methods 
whereby plants disperse their seeds. 
1. Wings or folds to the fruit or seed. 
Parachutes to the fruit or seed, 
Hooks or barbs to the fruit or seed. 
Bladders to the fruit or seed. 
Minuteness of the seeds or fruits. 
Hurling of the seeds by the parent. 
Fleshy fruits attracting birds, etc. 
Floating of seeds or fruits. 
Simulation of insects. 
The blowing about of the dead plant or of a part of it. 
Wings are flat light structures which offer a large surface and 
so enable the wind to blow the seeds farther than it would other- 
PO SIAN H YH 
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