Parasitic Fungi of Illinois. 155 
Roman numerals often following the above indicate the stage 
of development of the fungus; viz. I., ecidium; II., uredo; 
III., teleutospore. 
Key To THE GENERA OF UREDINE. 
I. Spores at maturity forming a more or less powdery mass. 
A. Spores with a permanent pedicel, mostly smooth and 
1. 
2. 
3. 
4. 
5. 
dark brown. 
Spores one-celled ..............2.00. Uromycss. 
Spores two-celled, septum horizontal. ..Puccrnta. 
Spores three-celled, septa in different planes. 
TRIPHRAGMIUM. 
Spores three or more celled, septa horizontal. 
PHRAGMIDIUM. 
Spores many-celled, septa variously placed. 
RAVENELIA. 
B. Spores with deciduous pedicels or none, one-celled, 
mostly roughened with minute projections, usually 
yellow or reddish-brown. 
1. 
a. 
b. 
c. 
d. 
Sorus with a peridium, spores produced in vertical 
chains, without pedicels. 
Peridium cup-shaped, rim-border mostly toothed 
or lobed and rectirved.............. ARCIDIUM. 
Peridium hemispherical or bow] shaped, deeply 
IMMETSEd 64 nde raqensc manne x ENDOPHYLLUM. 
Peridium elongated, usually cylindrical or coni- 
cal, soon split-fringed above ....... RastTELia. 
Peridium various, bursting irregularly, white, 
on Conifer ........ 2.00. ee eee PERIDERMIUM. 
2. Sorus without peridium. 
a. 
b. 
Spores produced in vertical chains, without ped- 
icels, usually accompanied with spermogonia. 
COMA. 
Spores produced on pedicels (deciduous), not 
accompanied with spermogonia ....... UREDo. 
II. ‘Spores at maturity embedded in gelatine, two-celled, sep- 
tum horizontal, pedicel long........ GYMNOSPORANGIUM. 
