Panicled Willowherb

Epilobium brachycarpum

Species distinguishing characteristics: 

  • Annual, branched near the top
  • Smooth stems with a shredding outer layer on lower portion
  • Cluster of pinkish-purple (or white) flowers with notched petals  
  • Smooth leaves, mostly alternate, wither at flowering
  • Smaller leaves clustered in leaf joints

Family Characteristics: 

  • Tall or branched clusters of flowers with 4 petals and 4 sepals
  • Flower parts are attached at the top of an elongated ovary
  • Pollen organs (stamens) in 4s (typically 8)
  • Fruits usually in a long 4-chambered capsule
  • White tuft of hair attached to each fruit

Growth habitat: 

Erect branched annual, 20-100 cm, from a taproot.  Highly variable species.

Leaves and stems: 

Lower portion of stems are hairless with a peeling outer layer.  Upper stem has short, stiff, glandular hairs.  Smooth short-stalked leaves, 1.5-5 cm, are folded at the midvein, are narrow, taper to a point, and have entirely or finely toothed edges.  Mostly alternate leaves will wither at flowering.  Smaller leaves often clustered in leaf joints.

Flowers: 

A branched cluster of pale pinkish-purple to white flowers, 0.2-3 cm long, sits atop the stem.  Petals are notched at the tip and are patterned with darker veins.  Club-shaped or 4 lobed pollen organs (stamens) are shorter than or equal in length to female organs (pistils).  Flower size is highly variable.

Roots: 

Taproot.

Seeds: 

Smooth or glandular-hairy capsules, 1.5-3.5 cm long, with stalks up to 2 cm long.  Seeds are bumpy and loosely attached by a tuft of white hair for wind dispersal. The seedpod splits into multiple sections, curling backward from their tip, and releases seeds.

Habitat preferences: 

Dry, sandy sites with disturbed soils in meadows, forests, open slopes, and along roads at low to subalpine elevations.

Interesting facts: 

The genus name Epilobium comes from the greek words epi, which means “upon,”and lobos, which means “a pod,” because the showy part of the flowers grow on top of (upon) the erect seedpods.  The high variability of this genus has made its members the subject of considerable research on plant taxonomy and evolution.  The mucilaginous shoots of many Epilobium species (and closely related Chamerion species) are edible raw or cooked.  

Biological Classification: