70 
MILDEWS, RUSTS AND SMUTS 
this genus. The teleutospore stage, being perennial in 
the tissues of the juniper, continues to produce teleutospores 
year by year, which are capable of infecting rosaceous plants 
and giving origin to the aecidium stage, but the teleutospores 
cannot directly infect a juniper, this can only result from 
infection by aecidiospores. The headquarters of this 
genus is in the LTnited States, where the malformations 
caused to junipers are known as " Cedar apples." 
PHRAGMIDIUM 
All the species are parasitic on plants belonging to the 
order Rosaceae, roses, brambles, etc. The aecidia form 
small yellow pustules, and are not enclosed in a peridium, 
as in Puccinia, but the heap of spores, produced in chains, 
is surrounded by paraphyses. The uredospore sori resemble 
generally, those of the aecidia, and are also surrounded by 
paraphyses. The teleutospore sori usually form small black 
pustules on the under surface of leaves, and are often sur¬ 
rounded by a discoloured zone. Opinions differ much as 
to what is a species in this genus, counting the number 
of septa in a teleutospore, as followed by some, is of no value. 
Carefully conducted infection experiments can alone solve 
the problem. 
XENODOCHUS 
Teleutospore sori relatively large, convex, black. Spores 
composed of a single row of about lo—20 cells, deeply 
constructed at the septa, hence more or less resembling a 
string of beads. 
The genus is closely allied to Phragmidium, differing 
mainly in the relatively greater number of cells composing 
the spore. The two genera are united by some authors. 
CALYPTOSPORA 
The white aecidia grow in two rows, one row on each side 
of the midrib, on the under surface of the leaves of conifers 
belonging to the genus Abies, silver fir, and other species. 
The aecidiospores are in chains, the component spores 
being connected by a narrow neck, resembling beads some¬ 
what separated from each other on a string. The teleuto¬ 
spores form extended, swollen crusts on the branches of 
the cowberry. These crusts are whitish at first, then pink, 
and finally blackish-brown. 
ROSTRUPIA 
Parasitic on living leaves of Elymus arenarms, Lyme 
grass. Neither uredospore nor teleutospore sori are very 
