30 FLOWERLESS PLANTS 



Fern it is noticed that the backs of the leaves 

 are freely covered with brown patches. It is 

 very easy to see that these spots are kidney- 

 shaped, and on examination with a lens it 

 will be found that they represent mere scales 

 covering a number of tiny stalked bodies. 

 This will be clearly seen if a magnifying glass 

 is used, but under a microscope the true nature 

 of the brown patches will be even more plain. 

 The botanist calls each patch on the fern frond 

 a sorus, whilst the stalked bodies are known 

 as sporangia. Of course, these latter contain 

 the spores by means of which the fern plant is 

 reproduced. As soon as the spores are ripe the 

 covering shrivels up and the spore cases burst 

 open. The sudden opening of the sporangium 

 is brought about by reason of the fact that, 

 when ripe, a row of hard cells which occupy 

 about three-quarters of its length acts like a 

 spring, tearing apart the walls of the case. 

 Thus the spores inside are thrown out into the 

 world, and, being very light, float away on the 

 breezes. 



A spore, which is infinitely more simple than 

 any seed, has never, perhaps, been better 

 described than as a tiny spot of living matter ; 



