Primrose Family

Henderson’s Shooting Star © TCorelli

Primulaceae (prim-u-LA-see-ee)

Iconic Features

  • Simple leaves, often in basal rosettes
  • Flowers in umbels, often from a scape
  • Flower parts usually in fives
  • Stamens aligned with petals

Description (Jepson)

  • Eudicotyledons (eudicots) – a major lineage of flowering plants including most plants traditionally described as dicots and generally characterized by
    • 2 seed leaves (dicotyledon)
    • Netted (reticulate) leaf venation
    • Flower parts in fours and fives
    • Pollen grains with 3 pores (tricolpate)
    • Vascular bundles in stem arranged in a ring
    • Taproot system
  • Annual or perennial herbs or slightly woody plants
  • Leaves
    • Simple (not divided into leaflets)
    • Generally in a basal rosette; or may be opposite (2 leaves at each junction with stem) or whorled (3 or more leaves/flowers at each junction with stem)
    • Lack stipules (pair of leaf-like structures at the base of the leaf stalk)
  • Flowers
    • Inflorescence (flower arrangement) an umbel (a spoke-like flower cluster with stalks radiating from a single point)
      • Often on a scape (a leafless stem rising from ground level)
    • Bisexual, radially-symmetrical flowers
    • Flower parts usually in fives
    • Stamens (male flower parts) aligned in the middle of each petal
    • Ovary superior (above the attachment of other flower parts)
  • Fruit a capsule (a dry, multi-chambered fruit that splits open at maturity)


  • Approximately 600 species in the northern hemisphere
    • Includes shooting stars and the common garden plants primrose and cyclamen
  • Some plants in this family (e.g. shooting stars) are pollinated most effectively by sonication or “buzz pollination”
    • Flowers have specialized “poricidal,” tube-shaped anthers containing firmly-attached pollen and having, unlike most anthers, small openings, like a salt shaker, which regulate the dispersal of pollen
    • Only bumblebees, along with a few other native bees, can release this pollen by grasping the flower with their legs or mouthparts and vibrating their flight muscles without moving their wings
      • Watch this short video to see how buzz pollination works (KQED 2016)
    • Vibrating bees may generate forces 50x that of gravity–5x what fighter jet pilots experience (U. of Stirling 2020), causing pollen to “blast out” of the anthers (Zimmer 2013)
    • Buzz-pollinating bees make a distinctive, middle-C “raspberry” sound, which is higher pitched than the buzz of flight (Rosenthal 2008)
    • Only about 9% of the world’s flowers are buzz pollinated (Buchmann 1985)
    • A number of important agricultural crops, such as tomatoes and potatoes, require buzz pollination
    • Poricidal anthers have evolved several times in disparate plant families, an example of convergent evolution (de Luca and Vellejo-Marin 2013)
  • Scientific name from the included genus Primula, from the Medieval Latin phrase prīmula vēris, “little first one of the spring,” referring to the plants’ early flowering
  • Common name from Medieval Latin prīma rosa, “first rose”
  • Distinct from the similarly-named Evening Primrose Family (Onagraceae), which includes clarkias and sun cups
  • Represented by 2 species at Edgewood

See General References

Specific References

Buchmann, S.L. 1985. Bees use vibration to aid pollen collection from non-poricidal flowers. Journal of the Kansas Entomological Society 58: 517-525. JSTOR.

de Luca, P.A. and M. Vellejo-Marin. 2013. What’s the “buzz” about? The ecology and evolutionary significance of buzz pollination. Current Opinion in Plant Biology 16: 429-435.

KQED San Francisco. 2016, Jul. 9. This vibrating bumble bee unlocks a flower’s hidden treasure [Video]. Deep Look. YouTube.

University of Stirling. 2020, Jul. 29. Bees’ buzz is more powerful for pollination, than for defense or flight. ScienceDaily.

Zimmer, C. 2013, Jul. 11. Unraveling the pollinating secrets of a bee’s buzz. New York Times.

Browse Some Edgewood Plants in this Family