54 EXPERIMENTS UPON THE HETERCECISM OF THE UREDINES. 
the 25th May. On 11th June spermogonia appeared on one leaf. 
There were many pear trees in this garden, but this was the only 
pear leaf on which the fungus could be found. This leaf was 
gathered during the last week of September, and exhibited at Here- 
ford. It never got beyond the spermogonial condition. 
Podisoma juniperi and Roestelia lacerata. 
Exp. 4. — Two thorn seedlings ( Crataegus oxyacantha) infected 
on 10th April with Podisoma juniperi. On 24th abundance of 
spermogonia ; on 25th May perfect Roestelia lacerata on both these 
plants. 
Exp. 5. — Three similar plants were on 7th April infected with 
Podisoma juniperi very freely. 24th April the leaves were yellow 
with spermogonia ; 2 5th May perfect Roestelia was produced. 
Exp. 15. — Two similar plants infected on 17th April. On 6th 
May spermogonia noted, and on 3rd June the perfect Roestelia on 
both plants. 
Exp. 16. — Three similar plants infected on 17th April. On 
6th May spermogonia noted, and on 3rd June the perfect Roestelia 
on all these plants. 
Exp. 27. — On 11th May the leaves on the lower branch of a 
hawthorn tree in Mr. T. Pung’s garden were infected with 
Podisoma juniperi. On the 21st the spermogonia appeared on five 
leaves, which in due time developed into the perfect Roestelia. On 
no other part of this tree, nor on any other thorn, either bush or 
hedge, in this garden, was any specimen of either the spermogonia 
or the perfect fungus to be seen. 
Gymno sporangium juniperi and Roestelia cornuta. 
Exp. 43. — Five small plants of Sorbus aucuparia were on the 
29 th May infected with Gymno sporangium juniperi, sent by the 
Rev. James Keith from Forres; on 25th July spermogonia appeared 
on three leaves ; on 4th September the perfect Roestelia cornuta 
was observed. 
Exp. 44.— Five similar plants were infected on the 29th May. 
On 21st June yellow spots appeared; on 1st July spermogonia 
were seen, and on the 4th September the perfect Roestelia. 
Exp. 63. — One small mountain ash ( Sorbus aucuparia ) was in- 
fected on the 12th June with Gymnosporangium juniperi , sent by 
Rev. J. Keith from Forres. On 16th Aug. spermogonia were noted. 
Exp. 73. — A similar plant was on the 18th June infected with 
the same material. On 1st July spermogonia appeared, and on 
30th August the perfect Roestelia. It should be observed that I 
had never seen this fungus in Norfolk until it was produced by 
artificial infection with the Gymnosporangium. 
Puccinia graminis and sEcidium berberidis. 
Exp. 11. — On 14th April a three-year-old plant of Berberis 
vulgaris was infecte 1 with the germinating teleutospores of Puccinia 
graminis (on Triticum repens ), and covered with a large bellglass. 
As the supply of infecting material was on this occasion limited, 
