Mather Field Vernal Pools


 
Psilocarpus brevissimus
© T.K. Komura
Psilocarpus brevissimus
© Carol Witham
common name

Woolly Marbles

 
scientific name

Psilocarphus brevissimus

 
family

Asteraceae (sunflower)

 
habitat

vernal pools

 
size

plant up to 4 inches tall,
each "marble" 1 to 2 cm across

 
fun facts

Each fuzzy "marble" contains both leaves and flowers.

 
description

Member of the sunflower family. Each flowerhead is made up of 20 or more disk flowers. These are well hidden in the cob-webby fuzz. The plants are pale green.

The top photo shows the plants early in the season. The flowerheads are visible in the center of the leaves. The bottom photo is later in the season when the leaves curl up.

 
life cycle

Woolly Marbles are annual plants. They germinate as the vernal pool water warms and begins to evaporate in the spring. Once the water is gone, they grow quickly. Woolly Marbles can be seen from late April until the rains begin in the fall. The flowers are well hidden in the fuzz. They bloom in May.

 
ecology

Woolly Marbles are endemic to vernal pools. Endemic means they cannot grow in other environments because they are either too dry or too wet. The plants do not release their seeds until the rains come in the fall. This prevents them from blowing away into unsuitable habitats.

Woolly Marbles are able to grow in vernal pools long after many other vernal pool plants have dried up. Their fuzz keeps the dry air from touching the plant and stealing its moisture.

 
investigate

The individual flowers are very well hidden in the cob-webby fuzz of the plant. See if you can find the disk flowers in the Woolly Marbles by using your hand lens.

 
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