How to Identify Malva nicaeensis (Bull Mallow)

Malva nicaeensis is an annual or biennial herb in the Malvaea family known by the common names: bull mallow and French mallow. It is native to Europe, Asia Minor, and the Mediterranean. It has become naturalized in California.

Photo tips:

• If there are multiple plants in the picture, crop your photo to focus on the plant of interest.

• The following views are required to identify the species:
  ** A photo of the entire plant. Is it decumbent or upright? How tall is it?
  ** A side view of the flower. Are the petals the same length as the calyx? 2x? 6x? Are the epicalyx segments separate or joined? Wide or narrow?
  ** A close-up of the fruit enclosed in the calyx and one with the calyx peeled back or removed. Is the fruit smooth? Hairy? Wrinkled?

• Note that Malva plants without flowers and fruits generally can’t be identified to species and should remain at the genus level (i.e., Malva).

How to identify Malva nicaeensis:

• Height: Grows up to 6 dm (24 in).
• Stems: Erect or ascending to decumbent, prostrate or trailing. Densely hairy.
• Leaves: Round or kidney-shaped, 5 –7 shallow lobes with scalloped margins. The leaf blade is up to 12 cm (4.7 in) wide.
• Flowers: 1-4 small flowers in leaf axils. Flowers are white with faint pink and pink at the apex. Petals are blue when dry. Filament tube is hairy. There are 5 petals that are up to 2x as long as the calyx. Flowering stalks are about the same length as the calyx.
• Calyx/Epicalyx: The calyx grows larger after flowering, enclosing the fruit. The lower half of the epicalyx segments are generally fused to the calyx, not to each other.
• Fruit: Strongly reticulate, mostly glabrous, rarely hairy.
• Habitat: Disturbed places
• Peak Flowering Time: March – June

Similar Species:

• Malva multiflora (Cretan Mallow)
• Malva neglecta (Dwarf Mallow)

How to differentiate M. nicaeensis from M. multiflora:

• M. nicaeensis grows up to 6 dm (2 ft.); M. multiflora can be much taller (up to 10 ft).
• M. nicaeensis has smaller petals (up to 12 mm in length); M. multiflora has petals more than twice as long (up to 30 mm).
• M. nicaeensis petals dry bluish, usually with darker veins; M. multiflora petals dry brownish.
• M. nicaeensis has epicalyx segments that are fused to the calyx, not to each other; M. multiflora has epicalyx segments that are united for about ¼ of their length.
• M. nicaeensis has rugose (wrinkled) mericarps; M. multiflora has smooth mericarps.

References:

• A Guide to the Identification of Wild Mallows (by Jose Potter Butler, William Reinders)
• Calflora: https://www.calflora.org/app/taxon?crn=5353
• Jepson eFlora: https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=32602eFlora

• Keys:
  ** http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=119571
  ** https://www.inaturalist.org/journal/blue_celery/66193-malva-sylvestris-vs-multiflora-vs-nicaeensis-vs-parviflora-key

• iNaturalist:
  ** https://www.inaturalist.org/taxa/61043-Malva-nicaeensis
  ** https://www.inaturalist.org/projects/malva-nicaeensis-bull-mallow
  ** https://www.inaturalist.org/posts/73139-how-to-identify-malva-nicaeensis-bull-mallow

Publicado el diciembre 4, 2022 04:45 TARDE por truthseqr