167 BRITISH PHANEROGAMIC PARASITIC PLANTS. 
The Clover Dodder, a sub-species of the lesser Dodder, is very 
injurious to red clover if it gets a hold on a field. It will also 
attack Lucerne. Its life history is the same as the last species. 
Sometimes whole fields will become covered with it, and the crop 
entirely destroyed. It grows in circular patches. A most important 
precaution is that any clover seed containing Dodder should never 
be sown. If it appears in a field of clover steps should be taken at 
once to eradicate it before the seed is ripe. If noticed in time, the 
branches of the infected plants may be cut off without destroying 
the crown of the plant; but it is better to dig them up and burn 
them. Then most careful watch should be kept on the field, as any 
small plant of Dodder left will soon spread. 
The order OROBANCHACE® consists of two genera :—OROBANCHE 
(Broom-rape), of which there are eleven species, and LaTHr#A 
(Toothwort), one species. They are all fleshy herbs, destitute of 
leaves or chloroplyll; parasitica] on the roots of the other flowering 
plants or trees. 
The species of ORoBaNCHE are all much alike and rather difficult 
to determine, but each species has its particular host or hosts. Some 
of them are very rare. I will take OroBANCHE MINOR (Lesser 
Broom-rape) as the type of the genus. The stem is 6 inches to 2 
feet high, of a purplish colour, slender. The flowers are dull white, 
tinged and veined with purple, in shape somewhat like that of the 
Louse Wort or Yellow Rattle. The flowering head in a young state 
resembles a head of garden Asparagus. The seeds are very minute 
and deeply pitted, they weigh about 12,500 to the grain ; several 
hundred are produced by a single flower, and are very easily blown 
about. The root is bulbous and composed of very tightly compressed 
scales; is quite hard and solid, 
The propagation by seed is a very slow process, requiring three, 
and in some cases four years to produce flowering plants. The plants 
never appear above ground until they are ready to flower. Thismay 
