BRITISH HETER(ECIOUS UREDINES. 91 
I. On Centaurea nigra, L. II. aud III. On Carex are- 
naria, L. 
On the sea-shore, Hemsby, Norfolk. 
The Carices as a family are the hosts of many species of Puc- 
ciniæ. Thus in Europe they harbour Puccinia Caricis, Schum., 
P. limose, Magnus, P. sylvatice, Schrót., P. microsora, Körn., 
P. caricicola, Fckl., P. vulpina, Schröt., P. dioica, Magnus, and 
P. Scheleriana, Plow. 
In this country we have P. Caricis, Schum., upon Carer hirta, 
C. riparia, and probably other species ; and P. Scheleriana, Plow., 
on Carex arenaria. This last-named species is, so far as at pre- 
sent known, confined to C. arenaria. Its life-history has been 
already worked out by a series of experimental cultures, which 
established its distinctness from P. Caricis. It has its scidio- 
spores upon Senecio Jacobea (Aicidium Jacobee, Grev.). The 
details of these cultures have been published elsewhere *. 
In the summer of 1884, the Rev. Canon Du Port sent mea 
leaf of Centaurea nigra affected by a fine ZEcidium, which he haa 
gathered on the sea-shore at Hemsby, on the Norfolk coast. No 
record of an Zeidium on this host-plant being known to me, I 
was much interested in its life-history. De Candolle f, it is true, 
has described an Æcidium on Centaurea Cyanus, but this is 
clearly not the fungus in question. In July 1884 a visit was 
made to Hemsby and a number of specimens collected. Cen- 
taurea nigra is very frequently affected with a Uredo and Puc- 
cinia ; but always, hitherto, these spore-forms have been un- 
accompanied by any cidium. Hence the presumption was that 
the Hemsby ZEcidium was unconnected with the above Puccinia, 
and that it was an heteracious species. A careful examination 
ofthe Hemsby Centauree failed to disclose any Uredo or Puc- 
cinia upon them, although the Æcidium was abundant in all 
stages. An examination of the surrounding Grasses and Carices 
failed also, at this time, in throwing any light upon the subject. 
On 14th August, 1884, another journey was made to the spot, 
Which was more successful No Uredo or Puccinia could be 
found on the Centaurea; but upon Carex arenaria, which grew 
in the immediate vicinity, a Uredo and Puccinia were abundant. 
* Plowright, “On the Life-History of certain British Heterccismal Uredines,” 
Quart. Journal of Micro. Science, n. s. vol. xxv. pp. 167-170. 
T De Candolle, Flora Franç. vol. v. p. 90. 
