Flower:

Small clusters of short stalked white flowers, less than 1/10 inch long with 5 fused petals, the triangular lobes about as long as the floral tube, spreading to bent back (reflexed), the tips sharply pointed and often curved up (inflexed). The calyx lobes are broadly triangular, often wider than long, typically as long as the floral tube and distinctly angled or knobby where they overlap at their base. In the center of the corolla tube is the globe shaped ovary with two styles, shorter than the surrounding 5 stamens but with a prominent round stigma at their tip (capitate), the ovary depressed around their base. Stamens are attached to the petal far below the base of the sinus between the petal lobes, and barely extend past the mouth of the tube. Hidden inside the floral tube, surrounding the ovary, are fringed scales that are shorter than the stamens.

Leaves and stems:

Leaves are tiny and scale-like or absent altogether. Stems are hairless and slender, typically yellow to bright orange, forming wiry masses that twist around and are supported by the host plant. Along the stem are small appendages (haustoria), modified roots that penetrate the host plant and draw moisture and nutrients from it.

Fruit:

Fruit is nearly round (globose), around 1/10 inch in diameter, depressed in the center, the base cupped by the withered flower, the stamens often persistent.

Notes:

Field dodder is one of nine Cuscuta species either present (6) or historically documented (3) in Minnesota. It is distinguished from other 5-petaled Dodders by its flowers with sharply pointed tips that are often inflexed, and the angled or knobby calyx lobes. In specific regard to the weediness of C. pentagona is this quote from a research paper on the integrated management of it in crops: "Cuscuta pentagona, also known as bush-clover dodder, field dodder, five-angled dodder, and lespedeza dodder, is the most widespread and aggressive Cuscuta species in the world (Holm et al. 1997; Lanini and Kogan 2005; Parker and Wilson 1986). In various parts of the world it is considered a serious pest of alfalfa, cabbage, peppers, potatoes, carrots, onions, tomatoes, beans, peas, safflower, sugar and garden beets and other vegetable crops". That being said, In my nearly 40 years of work in horticulture and agricultural pest survey in Minnesota, I've personally never seen a weedy infestation on anything. In my ten years of intensive photographic field work on native wildflowers, I've only encountered C. pentagona four times in natural habitats and all four populations have been quite small.

All dodders are obligate parasites - that is they must obtain all their life support from a host species to grow and reproduce. When a dodder seedling germinates, it must quickly contact a suitable host upon which it immediately begins to twine around the host plant's stem, invading its tissure with "haustoria" that tap into the host's vascular system for moisture and nutrients, the initial seedling root quickly withers away. As the stems grow, they contact and invade more stems, even crossing over and connect to other suitable host species. While most dodders are associated with broad host range, some are fairly specialized to only a few species. All species of dodder are on the federal noxious weed list except for a number of natives (and several non-natives that are now wide spread), includng all species found in Minnesota. Still all dooders are "regulated" requiring federal permits for importation or transportation of seed.