DESCRIPTIVE FLORA 



SUBKINGDOM PTERIDOPHYTA 



FERNS AND FERN-ALLIES 

 Plants containing woody and vascular tissues. 

 They produce spores asexually, each of which, on 

 germination, develops into a prothallium or a 

 small thalloid body (gametophyte). The pro- 

 thallia bear the reproductive organs; the fe- 

 male organ is known as an archegone, the male 

 as an antherid. As a result of the fertilization 

 of an egg in the archegone by a motile sperma- 

 tozoid produced in the antherid, the asexual 

 state of the plant is developed (sporophyte) ; 

 this phase is represented by and popularly 

 known as a fern, a lycopod, or a quillwort. 

 About 6000 species of living ferns and fern- 

 allies are known. Several thousand fossil spe- 

 cies have been discovered. A great majority of 

 the living forms grow naturally in tropical re- 

 gions. Eighteen species are known to occur in 

 Royal Palm Hammock, and thirty-three addi- 

 tional kinds have been found in the neighboring 

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