Flower:

Flowers are in dense spikes at the end of stems than arise from the leaf axils. Individual flowers are creamy white to pale yellow, ¾ to 1 inch long and tubular. The upper lip is longest and curves down over the end of the lower lip.

The bracts are lobed and toothed, with long hairs around the edges. The bracts are twisted so that the flowers are turned sideways. From the top of the plant the arrangement resembles a pinwheel.

Leaves and stem:

Leaves are up to 4 inches long and 1 inch wide, hairy, with small rounded lobes that have tiny teeth around the edges. Attachment is opposite, with each pair at right angles to the pair below it. Leaves are mostly about the same size, but are much smaller near the flowers. The main stem is covered in short hairs but may become smooth with age.

Fruit:

Fruit is a capsule, open at the top, containing numerous small seeds. The capsules persist through winter.

Inside are numerous irregularly shaped wrinkly brown seeds, each 1 to 2 millimeters long

Notes:

I first noticed this plant in mid June when it was sprouting and about a foot tall. I checked its progress almost every week and didn't see the first flowers until more than 2 months had passed. It was an agonizing wait. The leaf shape and flowers are similar to related species Wood Betony (P. canadensis) but that species has mostly basal leaves, is a smaller plant, and blooms in spring. Swamp Lousewort is partially parasitic; common host plants are asters and native grasses. All of the Pedicularis species were formerly in family Scrophulariaceae (Figwort) but have been reassigned to Orobanchaceae (Broomrape) along with other parasitic plants.