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Paper Birch Seeds Dispersing

Paper Birch (Betula papyrifera), also called White Birch, produces separate male and female flowers on the same tree, both in the form of catkins (cylindrical clusters of flowers). The catkins form in the fall and overwinter in a dormant state. In the spring they mature as the leaves develop, becoming pendulous. Male catkins are 2-4 inches long, whereas female catkins are usually 1–2 inches long. Both male and female flowers lack petals, enhancing wind pollination. After fertilization occurs, the male catkins wither away, while the female catkins droop downward and become cone-like.

The mature female catkins consist of tiny winged nutlets that are located behind three-lobed, hardened, modified leaves called bracts. Both winged seeds and bracts are usually dispersed by the wind during the fall and early winter. Birch bracts are species-specific — different species of birch have different-shaped bracts, allowing one to identify the species of birch that a bract comes from. Those of Paper Birch (pictured) look somewhat like soaring birds.

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4 responses

  1. Barbara Deal

    Hi Mary, I sent you a message a bit ago because I hadn’t received my 2021 calendar. I am wondering if you got my message. Thanks! Barbara Deal 802 453-2558 or Thanks Mary! I so love your daily nature.

    Sent from my iPad


    December 28, 2020 at 11:30 am

  2. Red in the face to say I’ve been stockpiling Naturally Curious posts for some time in my inbox because I wanted to savor them and learn a bit about a lot of things all at once(!). What was I thinking? I’ve been well acquainted with this tree for 40 years and learned something new from this little post. Thanks, Mary!

    December 28, 2020 at 12:19 pm

  3. Alice

    My morning ”Comment’ was being edited & disappeared 🤔’ I wrote: interesting info, The catkins are pretty on the 3 Black Birches we have, near the street, but when they fall off…what a mess!

    December 28, 2020 at 3:56 pm

  4. duke liddell

    I paid for a calendar for a friend who hasn’t received it as yet

    Thank you R Duke Liddell


    December 28, 2020 at 8:35 pm

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