BRITISH HETER(ECIOUS UREDINES. 97 
leaf bearing spermogonia. This is the only case in all my cultures 
in which the scidial mycelium did not perish during the winter. 
Unfortunately the spermogonia were employed for another experi- 
ment, so that it is uncertain whether the Restelia would have 
been subsequently developed. It is most likely that a bud was 
infected by one of the promycelial spores, as the experiment was 
made rather late in the summer of the preceding year. 
Three experiments with @. juniperinum on Pyrus Malus and 
one on Pyrus vulgaris were without result. 
G'YMNOSPORANGIUM JUNIPERINUM. 
: : . Date of |Date of fir: 
No. Infecting material. Plant infected. infection. result. st 
43. | G. juniperinum. Sorbus Aucuparia. 29 May | 25 June 
4. » n » ” » 21 June 
45. „ » » ” ” — 
63. » » » » 12June | 16 August 
73. » » „ » 18 June 1 July 
408. » » » » 23 June —— 
409. ” ” » » » 2 July 
407. T " Pyrus Malus. 22 June 
426. » » » » 7 July — 
429. ” » » » 8 July — 
430. » n P. vulgaris. ©» — 
Gymnosporangium fuscum, DC. 
It has hitherto been generally accepted that this Gymno- 
sporangium has its mcidiospores exclusively confined to Pyrus 
communis, as was originally demonstrated by (Ersted. The 
experiments of Rathay also tend to confirm this, as he was unable 
to produce any zcidiospores for this Gymnosporangium upon the 
six last plants previously enumerated in the table of his negative 
results. In some cultures whieh I made in May 1882, however, 
I found that G. fuscum was capable with me of giving rise to 
æcidiospores upon Crategus Oxyacantha. At the time I regarded 
this result as possibly arising from some accidental admixture of 
foreign spores; and before venturing to publish results at variance 
with preceding investigation I considered it necessary that my 
cultures should be many times repeated. In my investigations 
into the life-history of G. fuscum, 53 separate cultures have been 
made. In 80 cases G. fuscum was placed on Crategus Oxyacantha, 
86 per cent. of which were followed by the appearance and 
development of a Restelia. There can be no question therefore 
that G. fuscum, as it occurs in this neighbourhood, has :cidio- 
