Pedicularis canadensis is a perennial, hemiparasitic herb, (Hedberg et al. 2005), stems hollow, clumped, 15-40 cm tall, hairy, gray-green, often tinged with red; from a short, thick rhizome, roots fibrous.
Leaves alternate, mostly basal, stalks often longer than blades; blade 5-15 cm long, 2-5 cm wide, narrowly oblong to elliptic, pinnately lobed, fern-like, lobes deeply toothed to lobed (Radford et al. 1968); stem few, leaves becoming reduced, almost stalkless, small and bract-like in flower spike.
Flowers yellow, (sometimes purple), 1.8-2.2 cm long, bilaterally symmetrical, corolla 2-lipped, upper lip deeply arched lower lip to 1 cm long (Yatskievych 2006); calyx 4-lobed, green, very hairy, tubular, split in front; stamens 4 covered by upper lip; ovary superior; inflorescence of dense spikes 3-5 cm long; blooms April-June; pollinated by bumblebees including: Bombus fervidus, B. griseocollis, B. impatiens, B. nevadensis and B. pennsylvanicus (Macior 1968).
Fruit a dry capsule 1.2-1.6 cm long, with several flat seeds; stalk elongating to 20 cm in fruit; fruits May-July (Radford et al. 1968).
Wetland status: FACU.
Frequency in NYC: Very infrequent.
Habitat: Understory of undisturbed woods, soil pH 4-7, tolerant of shade, moderately tolerant of fire, intolerant of drought, salt, anaerobic soils (USDA, NRCS 2006).
Notes: A partial parasite (hemiparasitic) on the roots of many herbs and woody plants (Rhoads and Block 2000) forming root grafts (hautsoria) that take nitrogen, water and other nutrients form the host plant. Wood-betony is not a full parasite since it uses the extra nutrients to increase it’s own photosynthesis. It has been found to cause decreased growth in parasitized plants when nutrients and water are limited (Hedberg et al. 2005). Plant family listed as Orobanchaceae in Flora of Alabama and The Plant list http://theplantlist.org.