3i6 



A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 308. — Polyporus betidimis. Fruiting body from 

 the lower surface to show the \ery small pores. 



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Fig. 309. — Polyporus betidimis. Transverse section 

 through a portion of a fruiting body to show the 

 pores lined with a hymenium forming basidia. 



from the longitudinally running hyphae, which grow out and form a solid 

 layer of cells at right angles to the length of the tube. It is from among 

 these cells that the basidia grow out. They are somewhat larger than the 

 sterile cells of the hymenium and project slightly into the cavity. Each 

 basidium develops four short sterigmata from which four basidiospores 



