426 CLASS BASIDIOMYCETEAE 



Teliospores compound, two to a pedicel (see also Earlea). 



Teliospores easily separable, not surrounded by a conspicuous common mem- 

 brane, pedicels fascicled at base; spermogonia subcuticular. 



Tranzschelia 

 Teliospores not separable, surrounded by a distinct common membrane. 

 Outer membrane gelatinizing when wet; spermogonia subcuticular. 



Uropyxis 

 Outer membrane not gelatinizing when wet (except in the case of 

 Gymnosporangium) . 

 Spermogonia subcuticular; aecia caeomoid; no uredia. Gymnoconia 

 Spermogonia subepidermal. 



Pedicel and teliospore Avail gelatinizing when wet; aecia cupulate or 

 cornute; uredia wanting except in one species. Gijmnosporangium 

 Pedicels not gelatinous when wet; aecia cupulate or (more rarely) ured- 

 ioid.; apex of terminal teliospore thickened or papillate. 



Puccinia 

 Teliospores compound, several in a row (one species of Earlea has simple telio- 

 spores and several only two teliospores to a pedicel); spermogonia 

 subcuticular. 

 Teliospores with two to three lateral pores, smooth or more often verrucose; 

 basal portion of pedicel inflated in water; uredia present; aecia 

 caeomoid. Phragmidium 



Like the preceding but basal portion of pedicels not inflated in water; uredia 

 absent except in one species; aecia caeomoid (often included in 

 Phragmidium) . Earlea 



Terminal teliospores with one pore, the others with two, near the top; mostly 

 smooth, pedicel short, not swelling in water; uredia wanting; aecia 

 caeomoid. Xenodochus 



Teliospores with one pore in each cell, firmly united, smooth; pedicel elongated, 



not swelling in water, aecia uredioid. Frommea 



Teliospores with one pore in each cell, smooth, easily separable, pedicel very 

 short; aecia uredioid. Kuhneola 



Teliospores compound, consisting of a basal teliospore attached to a long pedicel 

 and two horizontally lying teliospores at its top; aecia uredioid, 

 spermogonia subcuticular. 

 Teliospores verrucose; uredia with paraphyses. Triphragmium 



Teliospores spiny; uredia wanting. Nyssopsora 



Teliospores numerous in a head, subtended by hyaline cysts. 



Ravetidia 



Key to the Commoner Mostly North American 

 Genera of Family Ustilaginaceae 



{Based on Clinton, 1906) 



Teliospores separate. 

 Sori dusty at maturity. 



Without definite false membrane. Ustilago 



With false membrane of fungus cells. Sphacelotheca 



Spores more or less agglutinated at maturity. 



Spores firmly agglutinated into tubercular nodules. Melanopsichum 



Spores developed around a central columella (rarely dusty). 



Cintradia 



