Fruticose thallus. a thallus consisting of rounded or flattened, vertical 

 or ascending branches. Also called fruticulose thallus. 



Gonidium (Gonidia), a term applied to the symbiotic algae of lichens. 



Granule (adj. Granulose), a minute thalloid elevation firmly adherent 

 to the substratum, usually bearing an indistinct upper cortical layer. 



Hymenium, see Thecium. 



fiypolithic, occurring below the surfaces of rocks. 



Hypophloeodal, referring to that portion of the thallus or other struc- 

 ture of lichens occurring beneath the surface of the bark. 



Hypothecium, the dense hypal tissue immediately below the thecium. 



Individualism, a form of symbiotic relationship existing' between two 

 or more organisms in which the resulting organic structure is wholly differ- 

 ent from any of the symbionts and in which at least one of the symbionts 

 cannot exist independently. 



Isidium (Isidia), a small cylindric simple or branched thalloid out- 

 growth from the surface of the thallus. 



Medulla, the loose hyphal network in the interior of the thallus. 



Mutualism, a form of symbiosis in which the symbionts are mutually 

 beneficial. 



Mycorhiza, a term applied to the symbiotic association of fungi and 

 roots of higher plants (especially Cupuliferae). Divided into endotrophic 

 and ectotrophic mycorhiza according to whether the fungi occur within 

 the parenchyma-cells of the root or upon their exterior. 



Mycodomatiae, term applied to the group of symbiotic organisms 

 (I'hizobia) which have the power of inducing tubercular neo-formations 

 in the roots of plants. 



Nutricism, a form of symbiosis in which only one of the symbionts is 

 especially benefited. 



Paraphysis (Paraphyses), a slender simple or more rarely branched, 

 sterile filament among the spore-sacs. 



Perithecium, the hyphal tissue of the so-called Pyrenolichenes ( Ver- 

 rucariaceae) enclosing the thecium. 



Phyllocladium (Phyllocladia), a small highly assimilative branch of 

 fruticose thalli. (This term is often applied to all secondary thalli.) 



Podetium (Podetia), the elongated alga-bearing apothecial stalk of 

 lichens developed from the primary thallus. (Usually applied to the ver- 

 tical thallus of a Cladonia.^) 



Primary thallus, a term referring to the thallus from which the podetia 

 develop. 



Pycnidium (Pycnidia), the structure upon the thallus of lichens con- 

 taining the so-called stylospores. (Perhaps closely related to the sperma- 

 gonium.) 



