Chances of Life 243 



small should have been able to preserve Hving germs 

 within them for so long a time is a wonderful proof of 

 their great tenacity of life. 



Generally speaking, it seems that the seeds of wild 

 plants have the advantage over the cultivated in this 

 respect. They retain their vitality longer; but then, on 

 the other hand, there are not so many of them. Culti- 

 vated plants usually produce most seed— except, of course, 

 where blossoms have been doubled or fruit improved at 

 its expense. 



When one considers the vast quantity of seed produced, 

 and the ample contrivances for scattering it, it is surpris- 

 ing to find that, after all, many plants do not increase 

 their numbers at alL There are just about the same 

 number of them now that there were years ago — neither 

 more nor fewer. 



Take, for example, the common wild spotted orchis, 

 a single plant of which often bears as many as thirty seed- 

 vessels, each containing six thousand two hundred seeds. 

 Suppose that there were four hundred bad seeds to each 

 capsule, twelve thousand in all, which is a fair allowance, 

 one plant might still be the parent of one hundred and 

 seventy-four thousand others — enough to cover nearly an 

 acre of ground if the plants grew just far enough apart to 

 allow a proper amount of space to each. The descend- 

 ants of these, again, might more than cover the Isle of 

 Anglesey, and the great-grandchildren of the one original 

 plant would more than clothe the entire land surface of 

 the globe! 



This calculation was made by Mr. Darwin; and yet, 

 as he goes on to observe, the plant is actually not increas- 



