ORDER DACRYMYCETALES 449 



and the color varies from very light gray to dark brown, purple or even 

 almost black. The infected trees or branches are injured, perhaps not by 

 direct action of the fungus itself but by the protection it offers to the 

 many scale insects it harbors. 



The genus Uredinella is perhaps best placed in this family. Like Septo- 

 hasidium it is parasitic upon scale insects and forms small circular dark- 

 colored spots on the bark. The fungus is annual, not perennial as is 

 Septohasidmm. The top layer is a hymenium of ovoid to club-shaped, 

 brown basidial primordia (called " teleutospores " by Couch, 1937). These 

 are binucleate when young and nuclear fusion occurs within them. The 

 mature cells have two or three thick layers of wall especially at the apex, 

 and a distinct germ pore. When the fungus is wet with rain an epibasidium 

 emerges through the germ pore and forms a straight four-celled structure 

 on which four basidiospores are produced on distinct sterigmata. The 

 epibasidium may break off from the hypobasidium and apparently can 

 float around in a film of rain water. The insects are infected through the 

 mouth region and the dicaryon mycelium within the host produces coiled 

 haustoria much like those of Septohasidium. Besides the basidia somewhat 

 similar "uredo-mother cells" are produced and from their apices grow out 

 binucleate, elongated ellipsoid, slightly bent spores, called by Couch 

 "uredospores." It is suggested by Couch that this genus may well repre- 

 sent a stage intermediate between the Uredinales and Septohasidium. 



Order Dacrymycetales. As in the preceding order the spore fruits are 

 mostly gelatinous or waxy, drying down to a thin sheet or horny mass. 

 They vary from thin, broadly effused sheets to cushion-like, cupulate or 

 pileate structures, or cornute, coralloid or spatulate upright forms. No 

 species are known to be parasitic. They are almost exclusively confined to 

 dead wood, with or without bark. With very few exceptions the spore 

 fruits are colored some shade of yellow or orange to deep brown and the 

 basidiospores are mostly yellowish in mass. Conidia are frequently pro- 

 duced. Whether these correspond to the "oidia" of some of the other 

 orders is uncertain, for cultural studies and attempts to match and dip- 

 loidize different strains are as yet much to be desired. The basidiospores 

 are one-celled when ready to be discharged but in most species septa are 

 formed immediately after discharge, di■\^^ding the spore into 2, 4, or even 

 up to 12 cells. In a specimen of Dacrymyces studied by the author the 

 basidiospores became once septate before they were discharged from the 

 sterigmata. They germinate by the formation of hyphae or of yeast-like 

 buds from the various cells of the spore. 



The basidia are formed in a close hymenium or intermingled with 

 sterile hyphae, on the outer surface of resupinate forms or on definite 

 surfaces in various other forms. They start as binucleate terminal cells 

 soon thicker than the rest of the hypha. They are at first long cylindrical 



