474 



A TEXTBOOK OF BOTANY 



[Ch. X 



While the hymenium covers radiating gills in the forms 

 just considered, it clothes spinose projections in the Tooth 

 Fungi (Hydnum species), some of which have umbrella- 

 « shaped sporophores (Fig. 



331), though in others 

 they are flat incrustations. 

 Again, the hymenium 

 forms a lining to tubes 

 opening by pores, in the 

 large group of Pore Fungi. 



Tig. 334.-Sporophore of Fames ap- TheSe als0 haVe in SOme 

 planatus, and supporting trunk, in verti- cases the Umbrella-form 



"of tte ^ annual layers of hymenium, sporophores, and areeither 

 the lowest is the youngest. (After Buller, edible Or poisonous (Bo- 

 Researches on Fungi.) fe ^ Mg 33^ . but much 



more commonly (Polyporus species) they constitute the 



Bracket Fungi or Shelf Fungi of trees. Here the mycelium 



ramifies through the wood, which it gradually destrovs, 



thus making the tree hollow, while the 



sporophore has the form of a bracket (Fig. 



333), familiar on dying trees. These 



brackets are diageotropically horizontal, 



and often are perennial, forming each year 



a new layer of hymenium which covers 



the older (Fig. 334). 



Belonging also to Hymenomycetes are 

 the Coral Fungi (Clavaria, Fig. 335), of 

 which the branching sporophores are 

 tipped by red or yellow hymenium. 

 Another form (Exobasidium) infests the 

 ovaries of the Heath family, causing 

 them to swell in a manner simulating galls (page 203). 



Fig. 335. — Cla- 

 varia aurea; X 2- 

 (From Bailey.) 



Order 4- Gasteromycetes: the Puffballs and kin. 

 These, the highest of all Fungi, are in habit much like the 

 Hymenomycetes, but their sporophores, usually approx- 



