munitum – munitus (Latin), meaning ‘fortified’ or ‘armed’ (with teeth along serrated edges), in reference to pinna

Native range: Western US and Canada

Leaves:

• “fronds”
• grow from a woody rhizome
• up to 1.5 m. tall
• erect to arching
• pinnately compound
• leaflets (“pinna”):
  • dagger-shaped
  • serrate
  • alternate
• sori exist year-round on fronds

Reproduction:

• alternation of generations
• sori are round and in two rows, one on either side of pinna mid-vein

Other characteristics:

• evergreen, perennial, long-lived
• new fronds emerge from rhizomes early each growing season

Relevant info:

• in managed landscapes, often cut back in the spring to showcase the new growth
• used in floral industry
  • enormous quantities of leaves are harvested for backgrounds in funeral wreaths and other floral displays
  • exported to Europe

Ecology & Adaptations:

• native from British Columbia south to California, east to Montana
• forested areas throughout Washington
• found in moist coniferous woods, in open to deep shade
• from sea-level to midmontane
• abundant and widespread from central Vancouver Island and adjacent mainland south, less common further north
• spores dispersed by wind and water
• vegetative reproduction:
  • limited
  • can regenerate from rhizomes after top-kill but does not spread vegetatively
  • rhizomes are short
  • plants grow in separate, individual clumps but often form extensive populations
• very shade tolerant:
  • but can also grow in open areas
  • optimal growth can be achieved in light conditions that are as low as 3% of full sunlight due to low light saturation point at which photosynthesis proceeds efficiently
• adapted to dry conditions – cuticular waxes seal plant surfaces against excessive water loss and are complex mixtures of very-long-chain aliphatics (carbon compounds without rings)
• adapted to low nutrient conditions:
  • evergreen fronds preserve investment in photosynthesizing structures
  • mycorrhizae aid nutrient and water uptake are likely, based on research on other members of this genus
• fire-tolerant:
  • top-killed by fire
  • rhizomes likely survive low and moderate fires, where soil heating is not severe and soil remains intact
• wildlife:
  • herbivores include mammals, such as elk, black-tailed deer, mountain beavers, American black bears, and mountain goats
  • P. munitum communities also provide habitat for several bird species