MUSHROOM GROWING 



have been found under and associated with 

 roots of the herbaceous or shrubby forms 

 of Cistus and Helianthemum, although this 

 is not invariable. Those collected by the 

 w^riter at Ain Sefra were under Arte- 

 misia herba-alba (Plate XIIP, c), and re- 

 cently several new hosts have been added. 

 These flowering plants may be spoken of 

 with justice, I believe, as hosts, for the 

 parasitism, or at least partial parasitism, of 

 the terfas upon the roots of these plants 

 seems to be beyond question. 



The family Terfeziacece differs from the 

 truffle family, Tuberacece, especially in the 

 fact that in the former the veins, which 

 break the general internal tissue into dis- 

 tinct areas, have no outlet to the surface; 

 and further, the plants are all provided with 

 a root-like process, or rudimentary stipe, to 

 which the mycelium in the soil is attached. 

 The principal species of the terfas as at pres- 

 ent known are as follows : — 



Terfezia leonis Tul. is a species which is 

 believed to occur in Northern Africa, par- 



212 



