Bull Mallow (Malva nicaeensis) - Variation in Size within a County Park

On May 26, 2024, I noticed several Malva nicaeensis plants of very different sizes. The smallest one was no bigger than the palm of my hand (in breadth and height). The largest one was waist high (approx. 35 inches). Very interesting! Especially in light of the fact that Jepson eFlora states that M. nicaeensis only grows to 2-6 dm (23.6 in) tall.

Sample 1: https://www.inaturalist.org/observations/218510391
This plant was very tiny - no bigger than the palm of my hand (~3 inches in diameter; ~1.4 in tall). The flowers and fruits were also very tiny. This plant was growing in the hard-packed dirt on the trail under full sunlight.

Sample 2: https://www.inaturalist.org/observations/218510400
This plant was as tall as my hand (~6 in) and only a few inches wide. It was growing in the shade under sycamore and California bay trees.

Sample 3: https://www.inaturalist.org/observations/218510444
This plant was twice as wide as Sample 1, but the flowers and fruits were about the same size. It was also growing in hard-packed dirt in the middle of the trail in full sunlight.

Sample 4: https://www.inaturalist.org/observations/218640472
This one was knee high (~20 inches). It was growing in the shade under some oak trees. The tips of this plant had been nibbled on - perhaps by the nearby herd of cows, so it was probably once taller than the measured height.

Sample 5: https://www.inaturalist.org/observations/218640481
This one was lying prostrate on the ground, but when I raised the stem, it was waist high (~35 inches). There were three main stems and lots at the leaf axils along the stem. It was growing with milk thistles along the side of the trail in full sun.

Sample 6: https://www.inaturalist.org/observations/218640479
I also noticed some M. nicaeensis leaves infected with some sort of virus. This is a new observation for me.

Posted on May 27, 2024 07:07 PM by truthseqr