What’s a dichotomous key?
Help
- Group 1Lycophytes, Monilophytes
- Group 2Gymnosperms
- Group 3Monocots
- Group 4Woody angiosperms with opposite or whorled leaves
- Group 5Woody angiosperms with alternate leaves
- Group 6Herbaceous angiosperms with inferior ovaries
- Group 7Herbaceous angiosperms with superior ovaries and zygomorphic flowers
- Group 8Herbaceous angiosperms with superior ovaries, actinomorphic flowers, and 2 or more distinct carpels
- Group 9Herbaceous angiosperms with superior ovaries, actinomorphic flowers, connate petals, and a solitary carpel or 2 or more connate carpels
- Group 10Herbaceous angiosperms with superior ovaries, actinomorphic flowers, distinct petals or the petals lacking, and 2 or more connate carpels
Dichotomous Key to Families
See list of 186 families in this key-
1a. Plants typically reproducing by spores, seeds and fruits not produced; gametophyte independent of sporophyte; ferns and fern-like plants
-
1b. Plants typically reproducing by seeds, the seeds borne within a fruit or not; gametophyte dependent on sporophyte; seed plants
-
2a. Plants not producing true flowers; seeds commonly borne in strobili on the surface of a scale (embedded in a fleshy aril in Taxus), never enclosed in an ovary; styles and stigmas absent; trees and shrubs with narrow, scale- or needle-like, usually persistent, leaves
-
2b. Plants usually producing true flowers; seeds enclosed in an ovary; stigma(s) and usually style(s) present, elevated above the ovary; woody or herbaceous plants with various types of leaves
-
3a. Leaf blades usually parallel-veined (or the plants thalloid in some Araceae); seeds with 1 cotyledon; perianth typically 3- or 6-merous; vascular bundles scattered throughout the stem; secondary growth absent
-
3b. Leaf blades usually pinnately veined; seeds with 2 cotyledons; perianth typically 4-, 5-, or more, -merous; vascular bundles arranged in a ring around a central pith; secondary growth absent or present
-
4a. Plants definitely woody; secondary growth present (though difficult to detect in some genera)
-
5a. Each node with 2 or more leaves or leaf scars (i.e., leaves opposite or whorled)
-
5b. Each node with 1 leaf or leaf scar (i.e., leaves alternate; subopposite at some nodes in some Rhamnus and in Salix purpurea)
-
-
4b. Plants herbaceous or suffrutescent; secondary growth absent
-
6a. Flowers epigynous or partly so (i.e., ovary inferior)
-
6b. Flowers hypogynous or perigynous (i.e., ovary superior) or the flowers lacking a perianth
-
7a. Flowers zygomorphic
-
7b. Flowers actinomorphic or without a perianth
-
8a. Gynoecium apocarpous, appearing as 2 or more distinct ovaries (i.e., the flower with 2 or more pistils)
-
8b. Gynoecium composed of either a single carpel or 2 or more connate carpels, the ovary thereby superficially appearing as 1 (i.e., the flower with 1 pistil)
-
9a. Corolla gamopetalous
-
9b. Corolla absent or essentially so
-
-
-
-
-
-
-
Show photos of: Each photo represents one family in this top.