Common name: Field Owl’s-clover
Scientific name: Castilleja campestris
Family: Scrophulariaceae (figwort)
Habitat: vernal pools
Size: plant 4 to 7 inches tall, flower 6 to 8 mm across
Fun facts: Field Owl’s Clover often supports the parasitic plant Vernal Pool Dodder (Cuscuta howelliana) which is the yellowish string-like plant in this photo.
Description: Member of the figwort family. The flowers are long tubes with three inflated (balloon-like) lobes near the top. In Field Owl’s-clover the inflated sacks are bright yellow.
The other owl’s-clovers all have colorful, multi-lobed bracts. Only Field Owl’s-clover has simple, green, leaf-like bracts.
Life cycle: Field Owl’s-clover is an annual. It usually germinates after the water in the pools has become very shallow and warm. It blooms from April to May and can be one of the dominant species in a pool.
Ecology: Most owl’s-clovers require very specific environmental conditions for successful germination and growth. Some years there will be very few plants or even none, while other years there might be millions! Very little is know about how the owl’s-clovers are pollinated.
Investigate: Try watching a Field Owl’s-clover for a while to find out if any insects visit it. Be sure to look for small crawling insects as well as the flying ones. Do you think Field Owl’s-clover is pollinated by insects?