Bill's Botanical Forays

Common dodder or Scaldweed (Cuscuta gronovii Willd. ex Schult. var. gronovii) is the most common species of dodder in the northeastern part of the USA and adjacent Canada. Dodders are fascinating parasitic plants. After the seeds germinate, the seedlings in the shape of a thread must come in contact with a host plant or they will die. After they find a host, their terrestrial root withers and they latch on to the host.

The plant then sends out small structures called haustoria, which invade the host plant’s tissue and take nourishment from it. Usually, dodders limit their damage to small areas, but occasionally, they will take over a field of planted crops. Some dodders are very host specific, but ones like the common dodder, will parasitize a wide variety of hosts.

The plants in this little colony were parasitizing Korean Clover, an undetermined species of grass, and a member of the daisy family. Botanical identification of dodders is extremely difficult. There are several dozen species of dodder in North America and between 100 and 170 species, depending on whether one lumps or splits species, in the world.