6 
effects on the roots of trees and shrubs watered out-of-doors were 
not noticeable although they were no doubt harmful. But the 
only alternative to using Thames water was to let them die of 
drought. The injury was far greater among plants grown in 
pots and surface rooting herbaceous plants in the open which 
had to be supplied with water daily. This no doubt resulted in 
a gradual “ salting’ of the soil. Its effects were evident early 
in July when many plants showed signs of ill-health, but this 
was attributed to the exceptional heat experienced about that 
time. By the end of August the collections generally showed 
in the dead and dying leaves of many plants which had pre- 
viously been in vigorous health that something unusual was 
happening to them. The exceptional heat made it necessary to 
water and syringe often and copiously, and in the belief that 
drought was the evil the gardeners were instructed to supply 
more and more water both at the root and overhead. 
~The Temperate House is provided with four large storage 
tanks for conserving rain water, and this supply held out until 
mid-August, when Thames water had to be used. In no house 
was the damage more in evidence than in the section which is 
filled chiefly with Himalayan Rhododendrons. The foliage of 
many was badly injured within a few days after the Thames 
water was used, and in some cases the young shoots were killed 
outright; this continued for at least two months after the use 
of the Thames water had ceased. In addition to the leaf injury 
‘there is the very serious effect the salt has had on the health of 
the plants. A large number of seedlings of new Chinese 
Rhododendrons were killed, although kept carefully shaded. 
n the other hand many Australian, New Zealand and 
Tasmanian plants in the Temperate House do not appear to 
have been injured by the water. These include the Australian 
Acacias, Callistemons and other myrtaceous plants. 
In the Mexican wing of the Temperate House many plants 
were injured, some of them being entirely denuded of foliage at 
an early stage of the trouble. The worst sufferers were Jacobinia, 
Strobilanthes, Psidium, Oreopanax and Trevesia. Several of these 
were handsome specimens and they were entirely ruined. A tree 
of Ficus religiosa 30 feet high lost every leaf, and a large specimen 
of F. lyrata was killed outright. Tree ferns, which have been a 
striking feature in this house for many years, showed early signs 
of injury. The specimens of Cyathea Dregei and Hemitelia 
semipinnata var. gigantea and Davallia platyphylla were killed 
to the ground. 
Among Chilean plants, two out of three examples of Embothrium 
coccineum were killed; a bushy specimen of Tricuspidaria 
dependens was killed, and 7’. lanceolata was badly injured. Four 
out of five plants of Lomatia ferruginea were killed; the only 
