Flora of Southwest Virginia

Class Magnoliopsida (the Dicots)
The diagram to the left represents one of the various systems that is used to classify the dicots (often referred to as the Cronquist system). It separates the dicots into 6 subclasses with supposed evolutionary relationships to each other illustrated by the "branching" patterns shown in the diagram. For instance, the Subclass Magnoliidae is placed in a basal position with the other subclasses branching out from it. This is meant to suggest that the Magnoliidae is the most ancestral of the dicot subclasses and that the other subclasses are derived from it (except for the Asteridae, which would be viewed as having been derived from the Rosidae).
More recent analyses have shown that this system may not accurately reflect the true evolutionary relationships within the dicot group.
However potentially inaccurate, the Cronquist system does provide a convenient means of classification of the less inclusive dicot taxa such as families, genera, and species. See the table below for the placement into these subclasses of the dicot families found in Southwest Virginia.

Diagram and subclass membership from: Cronquist, A. 1988. The Evolution and Classification of Flowering Plants. 2nd Edition. New York Botanical Garden, Bronx, New York.


 
Dicot subclasses
Some typical subclass features
Families found in Southwest Virginia
Magnoliidae
Flowers with a well developed perianth 
of separate parts (though, often with 
undifferentiated calyx and corolla, or
with corolla absent). Stamens numerous. 
Gynoecium apocarpus.
  1. Magnoliaceae -  Magnolia Family
  2. Annonaceae - Custard Apple Family
  3. Lauraceae -  Laurel Family
  4. Ranunculaceae -  Buttercup Family
  5. Berberidaceae -  Barberry Family
  6. Menispermaceae -  Moonseed Family
  7. Aristolochiaceae - Birthwort Family
  8. Papaveraceae - Poppy Family
  9. Fumariaceae - Fumatory Family
Hamamelidae
Usually woody plants with highly 
reduced, anemophilous, often 
unisexual flowers clustered into 
catkins. Perianth often very reduced 
or completely lacking. 
  1. Platanaceae -  Plane Tree Family
  2. Hamamelidaceae -  Witch Hazel Family
  3. Ulmaceae -  Elm Family
  4. Juglandaceae -  Walnut Family
  5. Fagaceae -  Beech Family
  6. Betulaceae -  Birch Family
  7. Urticaceae - Nettle Family
Caryophyllidae
Mostly herbaceous plants with 
unfused perianth parts. Gynoecium 
a syncarpous compound ovary 
with free-central or basal placentation. 
Plants typically producing betalain
pigments.
  1. Phytolaccaceae -  Pokeweed Family
  2. Chenopodiaceae -  Goosefoot Family
  3. Amaranthaceae -  Pigweed Family
  4. Caryophyllaceae -  Pink Family
  5. Polygonaceae -  Knotweed Family
  6. Cactaceae - Cactus Family
  7. Portulacaceae - Purslane Family
Dilleniidae
Woody and herbaceous plants 
having flowers with fused or 
separate corollas. Gynoecium 
a syncarpous compound ovary 
normally with parietal 
placentation.
  1. Hypericaceae -  St. John's Wort Family
  2. Tiliaceae -  Basswood Family
  3. Violaceae -  Violet Family
  4. Salicaceae -  Willow Family
  5. Brassicaceae -  Mustard Family
  6. Clethraceae -  Pepperbush Family
  7. Ericaceae -  Heath Family
  8. Diapensiaceae -  Diapensia Family
  9. Primulaceae -  Primrose Family
  10. Malvaceae - Mallow Family
  11. Styracaceae - Storax Family
Rosidae
Herbaceous or woody plants. 
Flowers with corolla fused, 
unfused or lacking. Compound 
leaves and stipules are common.
  1. Rosaceae -  Rose Family
  2. Fabaceae -  Legume Family
  3. Elaeagnaceae -  Oleaster Family
  4. Euphorbiaceae - Spurge Family
  5. Onagraceae -  Evening Primrose Family
  6. Cornaceae -  Dogwood Family
  7. Nyssaceae -  Nyssa Family
  8. Santalaceae -  Sandalwood Family
  9. Celastraceae -  Bittersweet Family
  10. Aquifoliaceae -  Holly Family
  11. Vitaceae -  Grape Family
  12. Polygalaceae -  Milkwort Family
  13. Aceraceae -  Maple Family
  14. Anacardiaceae -  Cashew Family
  15. Geraniaceae -  Geranium Family
  16. Oxalidaceae -  Oxalis Family
  17. Balsaminaceae -  Touch-me-not Family
  18. Araliaceae -  Ginseng Family
  19. Apiaceae -  Parsley Family
  20. Crassulaceae - Stonecrop Family
  21. Simaroubaceae - Tree of Heaven Family
  22. Hippocastanaceae - Horse Chestnut Family
  23. Saxifragaceae - Rock Breaker Family
  24. Staphyleaceae - Bladdernut Family
Asteridae
Herbs or woody plants. Flowers mostly with fused corollas. The number of stamens is normally equal or less than the number of corolla lobes. Gynoecium is most commonly a bicarpellate ovary.
  1. Gentianaceae -  Gentian Family
  2. Asclepiadaceae -  Milkweed Family
  3. Apocynaceae - Dogbane Family
  4. Solanaceae -  Nightshade Family
  5. Convolvulaceae -  Morning Glory Family
  6. Polemoniaceae -  Phlox Family
  7. Lamiaceae -  Mint Family
  8. Plantaginaceae -  Plantain Family
  9. Oleaceae -  Olive Family
  10. Scrophulariaceae -  Figwort Family
  11. Orobanchaceae -  Broomrape Family
  12. Bignoniaceae -  Bignonia Family
  13. Campanulaceae -  Harebell Family
  14. Rubiaceae -  Madder Family
  15. Caprifoliaceae -  Honeysuckle Family
  16. Dipsacaceae -  Teasel Family
  17. Asteraceae -  Sunflower Family
  18. Verbenaceae - Vervain Family
  19. Loganiaceae - Logania Family
  20. Hydrophyllaceae - Waterleaf Family

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