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135 
Dodder (Cuscuta trifolii, Bab.), (fig. 58) is the enemy most lo be dreaded. Space does not Parasites. 
permit us to give in detail the life-history of this parasite, and the means to be taken for its prevention 
and destruction. Later, we hope to give a full account of it. Dodder nsually gets into land as an 
impurity of clover seed. it germinates in the soil, and developes a thread -like stem which winds 
round the clover plant; from the thread-like stem numerous roots (haustoria) are produced, these are 
inserted into the tissues (soft bast) containing the nutritive juices, and the clover plant is sucked dry 
and killed. At first, the parasite takes a slight hold on the ground, but, as soon as it fastens on a 
clover plant, the part in the ground dies away, and the parasite lives entirely at the expense of the 
clover host. Various means have been recommended for its destruction. 
Another parasite is clover-rape (Orobanche minor, Sutt.). It often does considerable damage to 
the second crop. The roots of the parasite penetrate the soil and insert themselves into the clover 
roots from which they drain the nutriment required for their own purposes; in this way, the clover 
is killed. Some authorities assert that clover-rape can be destroyed by cutting the crop early and 
manuring with superphosphate, etc. In any case, clover rape should never be allowed to ripen its seed 
and any field on which it has broken out should be sown with a grass mixture, instead of clover. 
In certain districts of north Germany, a parasitic fungus, Peziza ciborioides, Fries., attacks clover 
and often does considerable damage (Rehm). Clover is also liable to various other fungoid diseases. 
A microscopic nematode worm, Anguillula devastatria, Jul, Ktihn., sometimes causes the rotting 
of clover. 
XXV. White clover. 
Trifolium repens, lL. 
Fig. A. Entire plant, in flower, shewing — the creeping stem giving off roots, the leaves, the Explanation 
peduncles and flower-heads. The peduncles are shortened to bring the flower-head into — of plate. 
the plate. 
, 4. The flower with its pedicel, seen from the lower surface. 
, 2 The same, side-view. 
»  o The same, with the calyx removed. 
» 4 The same as in fig. 3, with the standard removed. 
; 9. The same as in fig. 4, with the wings removed. 
, 6, The calyx and corolla removed, shewing the stamens. 
» 7. The pistil. 
, . The four-seeded fruit, crowned by the persistent style. 
» 9. The seed, from the broad side, shewing the radicle. 
, 10. The seed, from the edge, shewing the hilum. 
Botanical description. The stem is solid, and creeps along the ground.. As it runs along, it Botanical 
produces many branches, and gives off roots from the nodes. Each branch bears a few leaves with description. 
very long petioles. The long peduncles terminated by the flower-heads spring from the leaf axils. 
In fig. A the peduncle is made shorter than the petiole, to admit the flower-head to the plate. 
The leaflets are ovate or obovate, with finely toothed margins. The stipules are membranous and acute. 
The flower-heads or capitula are globular, solitary, and without bracts (ebracteate). Before and during 
flowering, the pedicels are erect; afterwards they bend downwards. The capitulum (to the left, fig. A) 
consists of two distinct parts; — the older outer portion with the pedicels and flowers reflected, and 
the younger central portion with the pedicels and flowers still erect. After flowering all the pedicels 
and flowers become reflected, The calyx is glabrous, ten-ribbed and about half as long as the corolla; 
