378 Annual Report for 1913 of the Botanist. 
the second crop of clover is cut. Any late-formed seeds, on 
account of their minute size, are completely removed by 
cleaning screens. 
Methods of checking the spread of clover-dodder have been 
asked for on several occasions. This dangerous parasite is still 
often introduced with clover seed, and consequently no sowing 
should be made without first ascertaining that the seed is free 
from it. Once it is established it seeds freely, and can, 
unfortunately, persist for years owing to its habit of attacking 
plants other than the clovers, such as thistles, knapweed, &c. 
Thoroughly burning infested patches with straw or chaff is as 
effective a method of dealing with the parasite as any. Failing 
this, good results can be obtained by spraying them with an 
ounce of an arsenical weed-killer dissolved in four gallons 
of water. 
Among other weeds reported on on one or more occasions, 
were hemlock, chervil, wavy hair-grass, rest harrow, dyers 
weed, scabious, knawel, creeping buttercup, and gout weed. 
General inquiries have been more numerous, and in some 
cases more interesting, than in former years. One of these was 
the case of a twenty-acre “ cherry orchard planted about thirty 
years ago. Although each season it presents a splendid blossom 
there has never been a good crop of fruit, and last year it was 
very poor.” Accompanying the enquiry was a box of flower 
buds, which the sender thought showed signs of some mildew. 
However, no mildew could be detected, and as the buds 
appeared to be normal, arrangements were made lor a frequent 
supply of material during the flowering and early fruiting 
stages. This was examined microscopically, with the result 
that both the stamens and the ovaries of the flowers were found 
to be perfectly normal. Other evidence obtained by bagging 
young inflorescences indicated that the flowers were sterile with 
their own pollen. The remedy in such cases is the simple one 
of intioducing a supply of the pollen of another cherry variety 
at the time when the flowers of the variety of which the orchard 
consists are fully open, fl his can be effected either by planting 
fresh trees of a suitable variety amongst the existing ones, or 
by grafting some of them with its scions. 
A similar case where an orchard of five acres of “ River’s ” 
plums generally failed to produce much fruit was traced to the 
same cause. 
There is a steadily accumulating volume of evidence to 
show that the system of planting one variety of fruit only in an 
orchard is not always desirable. Where its flowers will 
pollinate and fertilize themselves, if other circumstances are 
favourable, good crops should result. Where self-pollination 
results in few or no fruits setting the chances of crop failure 
