Orobonche ludoviciana, Nutt. (Myzorrhlza ludoviciana, Rydb.)

Native. Annual. Propagates by seeds.

Time of bloom: June to August.

Seed-time: July to September.

Range: Illinois to the Saskatchewan, southward to California, Arizona, and Texas. Habitat: Parasitic on several wild plants, but has also attacked tobacco.

This native Broom-rape has a wider range than either of its immigrant relatives, but it is only in localities suited to the growing of tobacco that it has shown itself to be harmful to plants of any value.

Stems solitary or clustered, sometimes simple but usually branched, three inches to a foot in height, rather stout, the stalk and the scales covered with minute, glandular hairs. Scales lance-shaped, numerous. Flowers in dense terminal spikes, each subtended by one or two bracts; calyx viscidly glandular, its five lobes acute and nearly as long as the tube of the corolla: the latter is purplish, slightly curved, and constricted above the ovary; upper lip two-parted, lower one with three lobes, pointed and entire. Capsule ovoid-oblong, two-valved, full of very fine seed. (Fig. 271.)

Means Of Control

If the ground is newly infested, the persistent hoe-cutting of the parasites from the roots of their hosts before any seed can be perfected, piling and burning them with oil-soaked straw or other litter, will be well invested labor. After the crop is harvested and cured, the stalks should be burned. Plant no more tobacco on the infested ground for several seasons.

Fig. 271.   Louisiana Broom rape (Orobanche ludoviciana),

Fig. 271. - Louisiana Broom-rape (Orobanche ludoviciana), X 1/3.