Primrose Family

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)

Notes

• 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 efficiently by “buzz pollination”
  • Flowers have specialized, tube-shaped “poricidal anthers”
    • Unlike most anthers, these anthers have firmly-attached pollen and small pores that act like the openings on a pepper shaker (Rosenthal 2008) to regulate dispersal of pollen
  • 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)
    • Although the pitch of this vibration is often described as a “middle-C,” the frequency of the vibrations is quite varied and complex, differing even within the same plant or bee species (Vallejo-Marin 2019)
  • Only about 6% of the world’s flowering plant species are most efficiently pollinated by buzz-pollinating bees (Vallejo-Marin 2019), including
    • Many plants in the Nightshade family (Solanaceae), e.g. blue witch (Solanum umbelliferum var. umbelliferum), found at Edgewood, and important agricultural crops such as tomatoes and potatoes (Campbell 2023)
    • Many plants in the Heath family (Ericaceae), e.g. Manzanita species and Pacific madrone (Arbutus menziesii), found at Edgewood, agricultural crops like blueberries and cranberries, and ornamental shrubs like azaleas and rhododendrons (Campbell 2023)
  • Buzz pollination is a good example of convergent evolution
    • Poricidal anthers have evolved several times in disparate plant families, as has the ability of some bee species to buzz-pollinate flowers (Vallejo-Marin 2019)
• 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

Specific References

Campbell, K. 2023, April 3. Buzz pollination is just for bees. Bird Town Pennsylvania. 

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

Rosenthal, S. 2008, June 11. Buzz pollination. Bay Nature.

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

Vallejo-Marin, M. 2019. Buzz pollination: studying bee vibrations on flowers. New Phytologist 224: 1068-1074.

General References

Calflora Database. 2014. Berkeley, California.

Calscape. 2018. California Native Plant Society.

Charters, M.L. 2015. California Plant Names: Latin and Greek Meanings and Derivations.

Charters, M.L. 2017. Southern California Wildflowers: Guide to the Pronunciation of Specific, Generic and Family Names.

Corelli, T. 2004. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California.

Elpel, T.J. 2013. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, Pony, Montana.

Flora of North America. efloras.org.

Harris, J.G., and M.W. Harris. 2013. Plant Identification Terminology: An Illustrated Glossary. Spring Lake Publishing, Spring Lake, Utah.

Keator, G. 2009. California Plant Families. University of California Press, Berkeley and Los Angeles, California.

Native American Ethnobotany DB.

Regents of the University of California. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.

Browse Some Edgewood Plants in this Family