How a Fern Grows 



Shake the dust out of the ripened fern and each particle, although 

 too small for the naked eye to see, has within it the possibilities 

 of developing a mass of graceful ferns. Each spore has an outside 

 hard layer, and within this an atom of fern-substance ; but it can- 

 not be developed unless it falls into some warm, damp place 

 favorable for its growth; it may have to wait many years before 

 chance gives it this favorable condition, but it is strong and patient 

 and retains its vital power for a long period. There are cases 

 known where spores grew after twenty years of waiting. But 

 what does this microscopic atom grow into? It develops into a 

 tiny-heart-shaped, leaflike structure which botanists call the 

 prothallium; this has on its lower side little roots which reach down 

 into the soil for nourishment; and on its upper surface are two 

 kinds of pockets, one round and the other long. In the round 

 pockets are developed bodies which may be compared to pollen; 

 and in the long pockets, bodies which may be compared to the 

 ovules of flowering plants. In the case of ferns, water is necessary 

 to float the pollen from the round pockets to the ovules in the long 

 pockets. From a germ thus fertilized in one of the long pockets, 



The life of a fern. 



a, pinna bearing fruit; b, a fruit-dot, enlarged, showing spore- 

 cases pushing out around the edges of the indusium; c, spore - 

 case, enlarged, showing how it discharges the spores. 



Prothallium, enlarged. 



Young fern growing from the prothallium. 



a little green fern starts to grow, although it may be several years 

 before it becomes a plant strong enough to send up fronds with 

 spore-dots on them. To study the structure of the spore requires 

 the highest powers of the microscope; and even the prothallium 

 in most species is very small, varying from the size of a pin-head 

 to that of a small pea, and it is therefore quite difficult to find. 

 I found some once on a mossy log that bridged a stream, and I 

 was never so triumphant over any other outdoor achievement. 

 They may be found in damp places in greenhouses, but the 



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