Plant of the Month: Birdbill Dayflower

Jul 25, 17 • 5enses, Plant of the MonthNo Comments

Birdbill Dayflower. Photo by David Moll.

By Mara Trushell

The Birdbill Dayflower (Commelina dianthifolia) remains underground living as tuberous roots for much of the year. The beauty of this dayflower may only be enjoyed after the monsoon thunderstorms saturate grassy openings and meadows within woodlands and conifer forests from 4,000-9,000 feet. By late July, relatively long, linear leaves grow alternately up thin stems that are topped with a large spathe (folded sheathing bract); this is the “bird bill.”

Beginning in August, during the cool morning hours, a single flower at a time emerges from the spathe. These flowers are comprised of three unique petals: two equal petals sit above a slightly smaller petal. Each is thin at its base, but then fans into delicate but wide vibrant blue petals; these just barely touch. In the center of the trio the stigma extends just beyond the vibrant yellow stamens which are set on filaments that are a deeper blue than the petals themselves. The display is complete when light catches the purple edges or stripes of the vibrant green spathe from which the flower emerged.

By the hot afternoon, this single flower often wilts, hopefully only after successful pollination, and the next day a new flower opens. This display continues through September. Then, once again, the Birdbill Dayflower reduces to its underground tubers until the next summer.

Western Spiderwort. Photo by David Moll.

[Author’s Note: Birdbill Dayflower is one of two common representatives of the Commelinaceae, Spiderwort Family, in Arizona. The second, Western Spiderwort (Tradescantia occidentalis) has a similar appearance at a glance. When observed in detail, the solitary spathes and flowers of the Birdbill Dayflower are quite distinct from the Western Spiderwort flowers, which are arranged in an umbellate inflorescence (multiple flowers creating a parasol shape) with purple petals that set broadly into slightly protruding sepals.]


Mara Trushell is a local natural science enthusiast.

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