- [Crown Copyright Reserve t. 
\ 
ROYAL BOTANIC GARDENS, KEW. 
BULLETIN 
“MISCELLANEOUS INFORMATION, 
No. 6] [1918 
XVIII.—_ON THE LIFE HISTORY OF THE ROSE 
BLOTCH FUNGUS. 
Srupres FRoM THE ParuortocicaL Lasoratory: VIII. 
N. L. Ancocx. 
(With Plate.) 
The fungus Actinonema rosae is familiar to all rose growers in 
this country who know only too well the black blotches it pro- 
duces on the leaves of many kinds of roses. i th 
. The fungus not only greatly disfigures the rose foliage, 
but it actually weakens the shoots through the destruction of the 
leaf tissues and the premature defoliation which bad attacks bring 
about 
in devising methods of control there has always been a difficulty, 
since mycologists until recently have been without information 
as to its method of hibernation and the origin of the new attack 
each season. pa this problem has been solved for the United 
States through Dr. A. Wolf, of Cornell University, having 
found an ascigerous oe on the dead leaves (Bot. Gaz. 1912, Sept. 
p. 218). The perithecia mature in April, we ascospores 
Ww aes infect the young sgt as it u this form 
Dr. Wolf has given fe generic name Diplocar. pon. The new genus 
balbiieh to the mily Miotothiyeiibede (Perisporiales). This 
family is characters d by having perithecia which are shield- 
shaped, flat, a round pore at the apex and a membrane formed 
only on the ais abe 1f examined other genera of this 
family, but came to the conclusion that the fungus was sufficiently 
distinct to be regarde d as a distin 
how that the eee Marsonia (to whic 
889, see Scottish Naturalist 
with which it agreed in som 
lace in Great Britain, # 
i eit has not yet been found. In 1916 1 
fo 
with Black Bloich and collect 
(5440.) Wet. 196—794. 1,125. 9/18 J.T. &8., Ltd. G@.14. Sch. 12. 
