ARTHUR: RELATIONSHIP OF GENUS KUEHNEOLA 507 
dehiscent, lenticular telia of the Schroeteriaster-Phakopsora appear- 
ance have entirely reversed this view. It has been found that 
with all other characters in essential agreement, the uredinium 
may have a membranous peridium opening by a central pore 
(e. g., Phakopsora punctiformis Diet.), or imbricated paraphyses 
united at their bases forming a pseudo-peridium opening by a 
central pore (e. g., Phakopsora Pachyrhizi Syd.), or a circle of 
hyphoid or incurved paraphyses often not higher than the spore 
mass (e. g., Phakopsora Vitis Syd.), or neither peridium nor para- 
physes (e. g., Bubakia Crotonis Arth.). 
The same situation appears to prevail in the genus Cronartium, 
as indicated by recent studies not yet published of tropical Amer- 
ican material. The same appears to be true of the expanded genus 
Cerotelium and to some extent of the contracted genus Kuehneola, 
as here outlined. These four genera appear to be closely related, 
having a like development of the uredinium with its several forms | 
of protective envelope or none, and a characteristic telium for 
each. Only in Kuehneola has the life cycle for some species been 
completed, and when this is done for the other genera, of course 
it is possible that some further sioner or emendation may be 
required. 
The following outline is presented to bring together in closer 
view the several groups of rusts considered in this paper. All 
short-cycle forms are excluded from consideration. The type 
species of the genus is given in each instance, and also the type 
species of genera reduced to synonymy. Under Cerotelium, 
Kuehneola, and Frommea, all species known to the writer which 
may be correctly placed under these genera, are here listed, but 
under Phakopsora and Crenartium only such species are given as 
are considered especially illustrative, or call for transfer from 
other genera. Other species heretofore published and accepted 
under Phakopsora and Cronartium, possessing known telia, such 
as given in the third volume of Sydow’s Monographia Uredin- 
earum, have not been listed. 
Only in a few instances is it possible to assign forms to their 
respective genera when only the uredinia are known. The at- 
tempts to do so by the Sydows (Kuehneola Garugae and Phakopsora 
Juelii), as well as those by the writer under the genus Physopella 
