3 PUCCINIA MALVACEARUM 
id overhanging it some Coltsfoot affected by the xcidium: 
iother tuft about ten yards off can be used as a control. The 
‘edo- and teleutospores will appear on the former tuft in about 
k to 21 days. If this is done late in the year (September) 
have found that only teleutospores are formed on the leaves 
‘the Poa. For the germinating ecidiospores see Figs. 27, 28, 
Puccinia Malvacearum. 
THe HoLiyvock Rust. 
This Rust differs from all the others that will be mentioned 
the simplicity of its life-history, and also in the fact that it 
not confined (as almost all the others are) to one kind of 
plant or even to a few, but ap- 
pears, so far as is known at 
present, to range over the greater 
part of a sub-family. It has 
been found on over 50 species 
of the Malvez, and it seems to be 
identically the same in every case. 
The mycelium develops in 
spring in the intercellular spaces 
of the young leaves and stems 
and produces little knots under 
the epidermis, on which a thick, 
round, hard, pale-reddish cushion 
of teleutospores is formed. These 
spores have short or very long 
pedicels according to their posi- 
tion; they are mostly typical and 
two-celled, but mesospores with 
only one cell are not uncommon, 
and occasionally a few may be 
met with having three or even 
fig. 29. P. Malvacearum, Ger- four cells, Most of them germi- 
minating spore; a, basidium nate at once, in the sorus, pro- 
breaking up into separate cells; 7. oes ‘ 
b, a basidiospore, x 600. ducing basidiospores in the usual 
belonging to nearly all the genera | 
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