326 CONVOLVULACEAE (CONVOLVULUS FAMILY) 



as many stamens as lobes set between their points and ex- 

 serted; ovary two-celled and style two-parted. Scales within 

 the corolla tube large, incurved, and toothed all round. Cap- 

 sules small, globular, two-celled, four-seeded, but often only 

 two or three seeds are developed. Seeds very small, rounded, 

 oval, grayish or yellowish brown; they are the most dangerous, 

 the most to be dreaded of all the impurities of clover seeds. No 

 seed should ever be harvested from a Dodder-infested clover field 

 and such seed should be unsalable at any price. Neither should 

 such a crop be harvested and fed as hay, for the seeds, uninjured 

 and viable, often pass the digestive tracts of animals, and may 

 be spread on other fields in the manure, not to speak of the seeds 

 that would be scattered wherever the hay was handled. Baled 

 hay is one of the sources of Dodder distribution. 



Means of control 



Sow clean seed. Infestation is often in patches where a single 

 seed or but a few have germinated. In such a case, cut the in- 

 fested plants close to the ground, before any seeds have ripened 

 if possible, pile them on the spot where they grew, let them dry 

 for a day or two, cover with straw, shavings, or some light rubbish, 

 soak with kerosene oil, and burn, being careful to get every thread, 

 cutting beyond the apparent limit of damage. Then stir the sur- 

 face soil of the patch lightly with rake or hoe, making a small 

 trench about the edge, cover a couple of inches deep with oil- 

 soaked chaff or rubbish, and again burn, in order to destroy any 

 seeds that may have matured and fallen to the soil. Or the soil 

 of the patch may be well sprinkled with crude carbolic acid. If 

 a whole field is infested, it will be best to plow the crop under; 

 but it must be done before the seeds ripen, indeed before they form, 

 else the land will be made unfit for occupation by clover or alfalfa 

 for seven or eight years. Or, the field may be pastured off by 

 cattle or sheep before the seed ripens ; but in that case the animals 

 must not be moved about, for bits of stalks may adhere in the 

 clefts of their hoofs, or unsuspected seeds may be in the droppings. 

 If seeds have been allowed to mature, the crop should be mowed, 

 dried, and burned on the spot, for Dodder-infested crops should 



