Previous Steps

• 1b – Alternate leaf arrangement on stem — go to 18
  • 18a – Leaf simple — go to 19
    • 19a – Thorns on stems — go to 20
      • 20b – Leaf margins serrated — go to 21

Current Step

• 21a – Thin, sharp thorns. No glands present on petiole near the leaf base — Hawthorn

• 21b – Thorns are thick, blunt at ends, almost branch-like. Very thin stipules may be present. Glands may be present on petiole near the leaf base — American Plum

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