Nodding Bur Marigold

aka nodding beggarticks, sticktight; Bidens cernua; Asteraceae (aster family)

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I found this annual plant along the sandy, exposed bed of the river when it was running very low, in mid-September.  Although bur marigold likes really wet soils, it is not considered an emergent aquatic.

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It can be found through most of the US and Canada, except for a few states in the south. Some authorities consider it weedy.

 

 

 

The more I see of composites, there more fascinated I am by them.  Here’s a close up of the disk flowers.

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By the way, it’s possible I’ve mis-identified this one.  There’s another, almost identical species called smooth bur marigold (Bidens laevis); I spent a long time poring over details on the fantastic New England Wild Flower Society and John Hilty’s Illinois Wildflowers websites. These have become my go-tos whenever the books fail me.

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Flower of the Day: Common Beggar-Ticks

aka devil’s beggar-ticks; Bidens frondosa; Asteraceae (aster family)

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At this time of year the asters are just about the only things blooming in the Potomac gorge.  This one is comprised entirely of disk flowers; the rays absent. The green parts surrounding the flower head are bracts.  20140908-DSC_0042

According to the USDA, there are 26 species (one of them alien) of Bidens found in North America.  Another one is Spanish needles, fotd 9/12.  This one is probably the most widespread of them.  It prefers moist soils and full sunlight but can tolerate some dry and shade; it’s prone to becoming a nuisance plant. While looking into the origin of the common name I tripped across a New Zealand website that featured it as Weed of the Month.

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The common name comes from the fact that the seeds hitch a ride on the fur (or clothing) of passing animals.