248 The Great World's Farm 



be independent even of cracks; this is what some seeds 

 are, especially a good many grass-seeds; for instead of 

 waiting to be buried, they set to work and bury themselves. 

 The seed of the grass Aristida, for instance, is inclosed 

 in a couple of husks tipped with bristles, each divided 

 into three fine tails, six or eight inches long, which stand 

 out in different directions more or less at right angles to 

 the seed. When the seed falls to the ground the tails 

 keep it upright, and as they dry and twist, they make it 

 turn round and round on its point, which is barbed with 

 flint; and so it bores its way into the earth, the barb hold- 

 ing it fast, so that it cannot be blown away by wind. 



Another self-burying seed is that of one of the crane's- 

 bills, which is nearly related to the geranium. The fruit 

 of this little plant consists of four or five miniature arrows, 

 which are the hardened and much lengthened carpels, each 

 having its ovary (containing a single seed) at the lower 

 end. At first they are fitted closely together round a 

 central spike, and form the "beak," with which we are all 

 familiar in the geranium. But when they are ripe, they 

 separate at the lower end, and begin to twist like a cork- 

 screw, still holding together at the tip, however, for a 

 time. Each arrow is fringed on the inner side with short 

 stiff hairs, and the ovary is pointed and barbed in a special 

 manner. They are readily carried by the wind therefore, 

 besides also clinging easily to the coats of animals; and 

 when at last they drop singly to the ground, the barbs 

 catch in the soil and hold them fast. The shafts of the 

 arrows twist more and more the drier they grow, and as 

 they twist, they turn the seed deeper and deeper into the 

 ground. 



Some seeds have many more difficulties in the way of 



