440 CLASS BASIDIOMYCETEAE 



hyphae there arise from the four cells of the epibasidium shorter or longer 

 arms reaching to the surface and there bearing the sterigmata and spores. 

 The basidial primordium may be an intercalary cell of the hypha although 

 more often it is terminal. In the genus Septohasidium it was pointed out by 

 Couch (1938) that the basidia among the more than 160 species represent 

 a number of different types. In the majority there is a distinct rather thin- 

 walled and hyaline hypobasidium which may send out the epibasidium 

 immediately or the hypobasidium may have a thick, colored wall and 

 serve as a resting spore until favorable conditions are present. The epi- 

 basidium is more often four-celled but in some species it is three-celled, in 

 others two-celled, and in two species it is one-celled. The basidiospores 

 become segmented into two to several cells and usually germinate by 

 sprout cells, when placed in water. 



Perhaps three families should be recognized in this order, although 

 Gaumann and Dodge (1928) recognized four. 



Auriculariaceae: parasitic on plants or saprophytic on dead plant material, 

 usually wood. Spore fruits often gelatinous but not so in some genera. Basidia 

 with no distinction into hypobasidium and epibasidium or these well dis- 

 tinguished. Clamp connections present in some genera, absent in others. 



Phleogenaceae: saprophytic on wood, bark, etc. No distinction into hypo- 

 basidium and epibasidium. Spore fruit stalked with a head of radiating, more 

 or less coiled hyphae, among which the curved basidia are formed, bearing 

 the four spores without visible sterigmata. Clamp connections observed. 



Septobasidiaceae (Order Septobasidiales, according to Couch, 1938): parasitic 

 upon scale insects with some of which they live in symbiotic relation. Basidia 

 usually with well-developed thin-walled or thick-walled hypobasidia and 

 one- to four-celled (mostly the latter) epibasidia, but hypobasidia sometimes 

 lacking. Basidiospores produced on distinct sterigmata. Conidia often pro- 

 duced. Clamp connections apparently lacking. 



Family Auriculariaceae. In the Auriculariaceae the following gen- 

 era should be mentioned as illustrating the various types of structure. 

 Eocronartium, with a single species E. muscicola (Fr.) Fitzp. is a perennial 

 fungus parasitic in the gametophytes of many mosses (see Fitzpatrick, 

 1918a, b). The cells of the mycelium are always binucleate and there are 

 no clamp connections. The mycelium is intracellular, passing from cell to 

 cell of the host but apparently doing little harm except that the produc- 

 tion of the sporophyte appears to be suppressed in the infected plants. At 

 the apex of the stem the hyphae pass out into the spaces between the 

 leaves and grow upward and parallel and form a gelatinous, club-shaped 

 sporophore on the outer surface of which the basidia are produced in great 

 abundance. The longitudinal hyphae of the sporophore turn outward to 

 the surface and there give rise to the basidia which as they elongate bend 

 almost at right angles so as to lie nearly parallel to the surface. The basid- 

 ial primordium is at first cylindrical or clavate, the major portion (epi- 



