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Key to Identifying Common Colorado Landscape Trees – 1   arrow

Current Step

Opposite leaf arrangement on stem


  • 1a – Opposite leaf arrangement on stem — go to 2


Alternate leaf arrangement


  • 1b – Alternate leaf arrangement on stem — go to 18



  • sub-opposite leaf arrangement1c – Sub-opposite leaf arrangement on stem. Some opposite and/or alternate leaves may also be present. Thorn at end of stem. Venation is arcuate (veins are arch-like extending from main vein, arching around the leaf margin, ending up near the leaf tip. — Common Buckthorn


  • leaves whorled1d – Leaves whorled (3 or more attached at the same node around the stem) — Northern Catalpa



November 2017