The Milkweed or Dogbane Family
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| whorled Apocynaceae leaves |
Apocynaceae flower |
The Apocynaceae are a family with a widespread but mostly tropical distribution, only a few genera extend into the temperate regions. The family contains 168-200 genera and 2000 species.
Click here for a distribution map of the Apocynaceae in the U.S.A.
Vegetative Characters | Reproductive Characters |
Diagnostic Characters | Economic Importance/Fun Facts
| Evolutionary Adaptations and Relationships | Glossary of Terms |
References and Links | Pictures
- perennial herbs, lianas, shrubs, and sometimes small trees
- often fleshy or woody tubers
- leaves simple, entire, opposite or whorled
- stipules lacking or minute
- sympetalous corolla of 5 lobes
- colleters at petiole base along with other projections on the perianth
- tissues have laticifers, sap usually milky
- nectar accumulates in outgrowths of the stamen-hoods and horns
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- flowers actinomorphic, perfect, hypogynous to slightly perigynous, and showy
- fruit a 2 or 1 (by abortion) follicle(s), seeds ovate to oblong with an apical tuft of silky hair
- superior to slightly inferior ovaries (2 distinct)
- placentation parietal
- gynostegium of 5 stamen, 1 stigma but either one connate or two distinct styles
- flowers rotate, funnelform or salverform
- inflorescence determinate, sometimes appearing indeterminate, occasionally reduced to a singly flower-terminal or axillary
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- synapomorphies = milky sap, highly modified gynoecium, and rbcl and matK sequences (Judd et al. 1994)
- symplesiomorphies = apical anther appendages, five-sided stylar head
- all but the genus Secamone have anthers with only two thecae
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- most taxa poisonous, many medicinal
- Catharanthus produces a compound used as an antileukemia drug
- many ornamentals - bluestar, milkweed, butterfly weed, natal plum, frangipani, periwinkle
- Apocynaceae are known for poisoning livestock
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- Apocynaceae (dogbane) and Asclepiadaceae (milkweeds) have been combined (Thorne 1992) into one single family deeming Asclepiadaceae a subfamily
- from cladistic analysis, the Apocynaceae are paraphyletic and the "Asclepiadaceae" monophyletic according to Judd et al. (1994)
- recognizing Asclepiadaceae as a family would make Apocynaceae a paraphyletic group whereas inluding it as a subfamily supports clear monophyly
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- colleter - a multicellular glandular appendage (often a trichome) which secretes a sticky substance
- theca - a pollen sac or locule of an anther
- laticifers - a cell or series of fused cells containing latex
- gynostegium - fusion of gynoecium parts to androecium parts, in this case stamens to stigma head
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- Walters, D.R. and D.J. Keil, 1996. Vasccular Plant Taxonomy, Fourth Edition. Kendall/Hunt Publishing Co. Dubuque, IA 52002
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Zomlefer, Wendy B., 1994. Guide to Flowering Plant Families. The University of North Carolina Press Chapel Hill, NC USA.
- Judd, W. S., C. S. Campbell, E. A. Kellogg, P. S. Stevens. 1999. Plant Systematics: a phylogenetic approach. Sinauer Associates, Inc. Sunderland, MA U.S.A.
- http://www.botgard.ucla.edu/html/MEMBGNewsletter/images/volume2/Whorledapocyn1.jpg
- http://www.utexas.edu/courses/zoo384l/sirena/species/plants/apocynaceae.gif
- http://www.lib.ksu.edu/wildflower/wildflower/milkweed.jpg
>- http://www.flwildflowers.com/wildflowers/peri77.jpg
http://www.art-bzl.com/Photos/milkweed.jpg- http://plaza20.mbn.or.jp/~mesemb/images/f_n_indicum.jpg
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| floral appendages |
5-star shape |
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| dehiscent follicles |
typical milkweed inflorescence |
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For questions or feedback, contact:
Kimberly Nelson