12 Key to Plant Classification

Dichotomous keys help improve pattern recognition and understanding of the descriptive terminology used to classify important distinctions among plants. The following dichotomous key can be used outdoors to classify a range of plants by type, growth habit, and reproductive method.

Practice

Use a dichotomous key for plant classification.

Key to Plant Classification

• 1.a. Plants rely on their closeness to water and absorptive green tissues above ground……………………………………………………… Non-vascular plant (go to 2)
• 1.b. Plants have a water conducting system that supplies above ground tissues with water and allows growth above ground ……………………………….. Vascular plant (go to 2)
• 2.a. Plants, (conifers and flowering) that reproduce by seed ………………………………………………………………….. Spermatophyte (go to 3)
• 2.b. Plants that reproduce by spores ……………………………… Pteridophyte (go to 4)
• 3.a. Spermatophyte that flowers and develops seeds within ovaries that mature into fruits …………………………………………………………………….. Angiosperm (go to 4)
• 3.b. Spermatophyte that flowers and develops seeds ‘naked’ in cones (conifer) ……………………………………………………………………. Gymnosperm (go to 5)
• 4.a. Plants with primary growth tissue only, lacking woody tissue like bark ………………………………………………………………………… Herbaceous (go to 6)
• 4.b. Plants with secondary growth tissue, like bark ……………………. Woody (go to 5)
• 5.a. Woody plants with one or few main stems ……………………………. Tree (go to 7)
• 5.b. Woody plants with multiple stems emerging from base …………….. Shrub (go to 7)
• 6.a. Non-woody tissue does not persist over one or more seasons; withers and dies back to fleshy crown, bulb, tuber, or rhizome ………………….. Deciduous herbaceous (go to 8)
• 6.b. Non-woody tissue and leaves persist over one or more seasons of growth …………………………………………………………… Evergreen herbaceous (go to 8)
• 7.a. Trees or shrubs that lose their leaves every autumn…………….. Deciduous (go to 8)
• 7.b. Trees or shrubs that are never entirely leafless ……………………………………………………. Evergreen or semi-evergreen (go to 8)
• 8.a. Herbaceous angiosperm that produces a single seed leaf; leaves have parallel venation; flower parts are in 3’s ……………………………………………… Monocotyledon
• 8.b. Woody or herbaceous angiosperm that produces a pair of seed leaves; leaves have netted venation; flower parts are in 4’s or 5’s …………………………….. Eudicotyledon