The Buttercups: Early Spring Wildflowers

April 8, 2024

It is a beautiful spring day, and I am walking along Berry Creek in the central grassland fields of the Mitigation Lands. The grass has grown a foot since the last time I was out here. The buttercup wildflowers are beginning to show their bright, shiny yellow petals throughout the pastures. 

There are eight different species of buttercup on the Mitigation Lands. The differences range from subtle to significant, depending on the species. Most are familiar with buttercups, a common roadside or garden wildflower that can act like a weed. Buttercups are a large group of flowers in the genus Ranunculus that usually have 5 to 10 yellow petals but can also have white petals. They can be annuals or perennials. Buttercups have also been known to be poisonous to mammals if eaten raw.

An old wives’ tale about buttercups is that if you hold a flower under someone’s chin and it reflects yellow, it shows that that person loves butter. This is something I was taught very young. Still, recently, I read about a research project at Cambridge University by scientists trying to understand what makes buttercups so reflective. It turns out that buttercups are built to attract pollinators. Their glossy petals curve inward to reflect light on the flower center. This, in turn, warms up the stamen that produces pollen, causing them to grow. This increases the chances of fertilization, plus the extra warmth attracts pollinators, like bees and hummingbirds. This is early-season food for them when there is not much else available.

The buttercups’ glossiness is attributed to the double epidermal layer on the petals. These are two flat surfaces containing space between them. This doubles the reflectiveness of the petals, increasing the amount of UV light given off. Many pollinators have eyes with UV receptors and are attracted to the buttercup petals. Different factors, such as scent and temperature, influence the relationship between pollinators and plants, and it seems that buttercups use visual appearance and temperature in a significant way to communicate with pollinators.

All of this information gives me more appreciation for the buttercups and how they have evolved strategies for their survival and propagation. A question to ask is, what other methods have buttercups evolved to increase their chances of pollination and survival?

The buttercup species in the valley live in a variety of water depths. One species, Ranunculus aquatilis (White-water crowfoot), floats on top of the water with its white petals on stems above the water surface and another species, Ranunculus occidentalis (Western buttercup) can grow in dry upland areas that are not inundated at all.

When you take your next spring walk, look for these early wildflowers and observe the pollinators that are attracted to them. See if a friend loves butter by holding a buttercup flower under their chin and looking for a bright yellow reflection. Be sure not to eat them! You will find buttercups in your yard and along roads. They are the abundant bright yellow flowers growing with purple camas in our Willits Valley.