48 



PUCCINI A MALVACEARUM 



and overhanging it some Coltsfoot affected by the secidium : 

 another tuft abuut ten yards <>tV can be used as a control. The 

 uredo- and teleutospores will appear mi the former tuft in about 

 14 to 21 days. If this is done late in the year (September) 

 I have found that only teleutospores are formed on the leaves 

 of the I'mi. For the germinating a^cidiospores see Figs. 27, 28. 



Puccinia Malvacearum. 



The Hollyhock Rust. 



This Rust differs from all the others that will be mentioned 

 in the simplicity of its life-history, and also in the fact that it 

 is 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 

 belonging to nearly all the genera 

 of the Malvese, 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 

 Ger . four cells. Most of them germi- 



minating spore ; a, a basidium na t e at once, in the SOHIS, pro- 

 breaking up into separate cells ; . . , , 

 b, a basidiospore, x 600. ducing basidiospores in the usual 



