EXOBASIDIACEAE 341 



''On the histology of Uredo dispersa Erik., and the mvcoplasm hypothe- 

 sis," Phil. Trans. Roy. Soc. London, B, 196: 29-^6, 1903. 

 Whetzel, H. H., H. S. Jackson, and E. B. Mains, "The composite Hfe 

 history of Fiiccinia podopbylli Schw.," /. Agr. Research, 30: 65-79, 

 1925. ' 



HO.MOBASIDIO.MYCETES 

 Hymenomycetes (Agaricales) 



As considered in this book, the As^aricales include 6 families of 

 funm. Some mycolos^ists regrard certain of these families as of 

 ordinal rank and the tribal groupings as of familial rank. These 

 6 families are separated as follows: 



1. Basidiocarps lacking; parasitic on yascular plants Exobasidiaceae 



1. Basidiocarps present; saprobic or parasitic 2 



2. Basidiocarps arachnoid, membranaceous, leathery or \yoody, 



effused, shelying or erect; hymenium plane Thelephoraceae 



2. Basidiocarps fleshy to cartilaginous; clayate to coralloid; hy- 

 menium amphigenous Clayariaceae 

 2. Basidiocarps fleshy gelatinous, cartilaginous, or leatherv% yariable 



in form; hymenium typically of spines or tubercules Hydnaceae 



2. Basidiocarps fleshy, leathery, or \yoody, resupinate, shelying, or 

 pileate; hymenium pitted, poroid, daedaloid, or lamellate 



Polyporaceae 

 2. Basidiocarps usually fleshy, mostly stipitate and pileate, a few 

 shelying; hymenium lamellate Agaricaceae 



Exobasidiaceae 



The fungi included in the Exobasidiaceae, approximately 30 

 species, are parasitic on leayes, stems, flo^^"ers, and fruits. Exo- 

 basidium typifies the family. Its species produce marked hy- 

 pertrophy and hyperplasia, especially on Ericaceae. Exobasidiiivi 

 'vaccinii deforms the shoots and leayes of cranberry, Oxy coccus 

 77?acro carp 071, and related species of A'accinium. Exobasidnn7i 

 rhododendri incites the formation of larsre yesicular stalls, 

 especially on the leayes of Rhododendron catawbiense and R. 

 7/iaxi77m77i. Exobasidni77i sy77iploci causes galls to form on 5y7;/- 

 plociis tinctoria. On Azalea E. discoideii77i may induce the for- 

 mation of hypertrophies 3 to 5 cm tall, \yhich resemble some- 

 what the basidiocarps of Cantharellus. 



LonCT afjo Woronin studied Exobasidium, and more recently 

 it was subjected to detailed study by Eftimiu and Kharbush 



