Previous Steps

• 1b – Alternate leaf arrangement on stem — go to 18
  • 18b – Leaf compound — go to 58
    • 58b – More than 3 leaflets — go to 59
      • 59c – Leaflet margins are medium-serrate — go to 64
        • 64b – Solid pith — go to 65

Current Step

• 65a – Leaflets up to 2 ½ inches long; all of uniform size. No milky sap from cut stem — European Mountain Ash

• 65b – Leaflets 2-5 inches long; with leaflets increasing in size towards the leaf base. Milky sap exuding from cut stem — Staghorn Sumac

Resources

• Identifying Broadleaf Flowering Trees and Shrubs, CMG GardenNotes #173
• List of trees in this key
• Glossary of Terms
• Front Range Tree Recommendation List
• Online CSU Extension publications on Tree and Shrub Selection