Valley Tassels or Narrow Owl’s-clover

Common name: Valley Tassels or Narrow Owl’s-clover

Scientific name: Castilleja attenuata
Family: Scrophulariaceae (figwort)
Habitat: damp grassland
Size: plant 4 to 12 inches tall, flower 4 to 6 mm across

Fun facts: Most Castilleja are hemi- parasitic (partially parasitic) on other plants.

Description: Member of the figwort family. The flowers are long tubes with three inflated (balloon-like) sacks near the top. In Valley Tassels, the inflated sacks have a series of pink, yellow and black spots which resemble tiny faces.

Note that the multi-lobed bract of Valley Tassels is white tipped. The other owl’s-clovers at Mather Field have purple multi-lobed bracts or simple, green, leaf-like bracts.

Life cycle: Valley Tassels is an annual. It germinates in the late fall or early winter. As the weather begins to warm in the early spring, the plants grow very quickly and bolt up through the grasses to bloom. Valley Tassels bloom in April.

Valley Tassels is a hemi-parasite on annual plants. The tips of its roots tap into the root system of the other plant and rob nutrients. Unlike the Vernal Pool Dodder (Cuscuta howelliana) which is a true parasite, the Castilleja can only steal a portion of the nutrients it needs and has to make the rest through photosynthesis.

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.