Vine Weeds of Missouri - Page 4
Dodder is a parasitic plant that lacks chlorophyll and therefore has a yellow-orange color. It has a spaghetti-like appearance, and its stems may be as thin as thread in some cases. There are at least 10 known species of dodder in Missouri. Because of the plant's parasitic nature, its seedling stems and roots can persist for only a short time if no suitable host is in close range for attachment. Once the stems attach to the host plant, a structure known as a haustorium penetrates the host plant. After the haustoria have begun extracting water and nutrients from the host plant, the dodder's stem breaks away from the soil surface and the dodder becomes totally reliant on the host. The plant will grow rapidly and soon have a dense mass appearance as it entwines around the host plants. Not all plant species are suitable hosts for dodder.
In Missouri, the primary hosts of dodder are members of the aster and legume plant families. Occasionally, dodder can be a serious pest of leguminous forage crops such as alfalfa and clover. The tiny yellow-orange seed produced by dodder can persist in the soil for years.