CHAPTER XXXII. 



FERNS (CLASS FILICINE^E). 



496. General characters. 



The ferns, because of the attrac- 

 tive foliage of many species, are 

 often grown for ornament, and 

 this has led to their being most 

 generally known, though com- 

 paratively few persons know their 

 structure and the course of their 

 life history. The fern plant has 

 a true stem, roots and leaves, 

 and in this respect is very dif- 

 ferent from the moss plant, where 

 the stem and leaves have resulted 

 from the differentiation of a thal- 

 lus. The leaves (often called 

 fronds) possess chlorophyll, and 

 perform the function of photo- 

 synthesis, while the roots are in 



Fig. 302. 



Walking fern (Camptosorus rhizophyllus). 

 Young ferns developing from the slender 

 tips of the leaves. 



To THE TEACHER. One of the ferns should be studied carefully in the 

 practical work. Prothallia can often be found growing spontaneously on the 

 soil of pots in greenhouses where ferns are kept. If not they can.be grown 

 from the spores. Often one can interest a gardener in the greenhouse to 

 assist in growing them or they can be grown in the laboratory. A per- 

 manent collection of a number of the local ferns, which the students could 

 assist in making, can be used to illustrate variations in habit, dimorphism, 

 etc. Where greenhouses or conservatories are near the students can visit 

 them to inspect tropical ferns as well as other interesting plants. If the time 

 allotted to the course is too short for practical study of the higher fern plants 

 dried examples of the horse tail, club mosses, etc., can be used for illus- 

 tration. 



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