312 PART III. THE CLASSIFICATION OF PLANTS. 



formed. These gonidia are termed basidiogonidia, with reference 

 to their mode of origin. 



The form of the compound gonidiophore, as also the relation of 

 its different parts, varies widely in the orders and families of 

 the sub-class. As the more minute peculiarities are described in 

 the account of these groups, only the important diversities are 

 now mentioned. In the familiar Auric ularieae, Tremellineae, 

 Dacryomycetes, Clavariece, Thelephorese, Hydneae, most Polyporese, 

 and some Agaricinse, the hymenium is exposed from its first devel- 

 opment, and the gonidiophore is consequently said to be gymno- 

 carpous. In Polyporus volvatus, species of Boletus, and in some 

 Agaricinse (e.g. sub-genera Armillaria, Psalliota, of the genus Agar- 

 icus, etc.) the hymenium is covered for some time by a membrane, 

 termed a velum partiale, as described above (see Fig. 222) ; the 

 gonidiophore is then termed hemi-angiocarpous. Finally, the whole 

 gonidiophore may be surrounded by a membrane, which is dehiscent 

 or indehiscent, and is then said to be angiocarpnus. This is due 

 to the fact that the gonidiophore is developed from the internal 

 portion of the primitive mass of hyphal tissue, the external por- 

 tion constituting the enveloping membrane. This arrangment 

 obtains in various genera of Agaricinse, such as Agaricus (sub- 

 genera Amanita, Fig. 222, Lepiota) and Coprinus, and generally in 

 the order Gasteromycetes. This membrane is termed, in the case 

 the Agaricinre, a velum universale ; in that of the Gasteromycetes, 

 a peridium. When it is dehiscent, and the 

 gonidiophore is stipitate, a portion of it re- 

 mains surrounding the base of the stipe as 

 a volva. 



In species belonging to all the families 

 of Hymenomycetes, except Clavariese and 

 Hydnese, and also in some other forms (e.g. 

 Nidularia pisiformis), certain large project- 

 ing sterile cells, termed cystidia (Fig. 223), 

 are formed in the hymenium, the function 

 of which is not fully understood. 



In. the higher Basidiomycetes (Autobasi- 



FIG. 220. Multicellular . v 



basidium of Tremeiia : diomycetes) the basidia are unicellular, but 

 a sterigma; p basidio- i n the lower forms (Protobasidiomycetes) 



gonidia. (x 350.) , . , . , .,, 



they are multicellular, either with trans- 

 verse septa (Pilacreae, Auriculariese), or with longitudinal septa 

 (Tremelline*, Figr, 220). 



