The Portulacaceae

The Purslane Family

Spring Beauty Claytonia lanceolata	Calandrinia spp.

The Portulacaceae family is made up of 19 genera and 500 species. Its distribution is widespread. It is usually found in warm and temperate climates. The most diversity is seen in western North America, southern South America and southern Africa. In the U.S. and Canada the most popular genera are Claytonia, Portulaca, Talinum and Lewisia. The plants are generally herbs to shrubs.

Click here for a distribution map of the Portulacaceae 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

Vegetative Characters

• annual or perennial herbs or suffrutescent shrubs
• often prostrate
• may have mucilaginous tissue with a bitter sap
• taproots or fleshy roots
• leaves variable (can be alternate, opposite or basal) usually stipulate
• stipules scarious or tufted hairs
• leaves are often succulent

Reproductive Characters

• synoecious
• small showy flowers with 5 (2-18) petals
• perianth usually 4-6 petal-like tepals
• inflorescence determinate and cymose (can appear racemose)
• flowers actinomorphic, perfect and hypogenous to half epigynous
• flowers subtended by two unequal bracts (calyx-like)
• often have extrastaminal nectariferous disc
• stamens as many as tepals, opposite or twice as many to numerous
• carpels 2-9 and connate
• fruit is a capsule, circumscissile or rarely a nut
• superior to inferior ovary
• 1 locule with basal or free central plancentation

Diagnostic Characters

• succulent leaves
• involucre of 2 unequal bracts
• perianth made up of petaloid, ephemeral tepals
• muscilaginous tissues
• many use C4 photosynthesis
• modified stipules-scarious or tufts of hairs

Economic Importance/Fun Facts

• some have edible green parts such as the common purslane Portulaca oleracea
• ornamentals
• many are poisonous (oxalic acid)

Evolutionary Adaptations and Relationships

• monophyletic group although in question
• may be separated into three different families
• Calandrinia may be paraphyletic
• many genera have a wide rage of numbers of chromosomes meaning they have a complex evolutionary history via the development of polyploidy
• genus Portulaca has a half inferior ovary

Glossary of Terms

• suffrutescent- woody base with herbaceous stems
• prostrate- lying flat on the ground
• stipulate- leaf with stipules
• stipules- pair of appendages at base of leaf
• scarious- dry membranous texture similar to an onion peel
• extrastaminal nectariferous disc- a nectar secreting disc on top of the ovary

References and Links

• Judd et al., 1999. Plant Systematics: a phylogenetic approach. Sinauer Associates, Inc. Sunderland, MA U.S.A.
• Walters, D.R. and D.J. Keil, 1996. Vasccular Plant Taxonomy, Fourth Edition. Kendall/Hunt Publishing Co. Dubuque, IA 52002
• Zomlefer, Wendy B., 1994. Guide to Flowering Plant Families. The University of North Carolina Press Chapel Hill, NC USA.

Pictures

Portulaca mundula	Pink Purslane Claytonia sibirica

Talinum triangularenotice bracts and tepals	Talinum triangulare

For questions or feedback, contact: Catharine Calandra