Thursday, September 1, 2011

Dryas octopetala – White Mountain Avens

Dryas octopetala - White Mountain Avens


Michael Compagno snapped the images above in Alaska of Dryas octopetala, which is commonly known as white mountain avens. A member of the rose family, it is a plant of cold boreal and arctic regions and it extends south from Alaska through Canada and into the United States by growing down the chain of western mountains. Each tiny, seedlike fruit, technically referred to as an achene, is equipped with a long feathery tail that aids in catching the wind and helps to disperse the seeds to new locations. These images were captured in August and it was the middle of autumn in Alaska. Thus, very few plants were in flower but many were in fruit. If Michael had visited earlier, he would have been greeted by many dozens of pure white flowers, held a few inches off the ground, and resulting in a spectacular display. According to Ladyman (see reference at the end of this post), the flowers face the sun and the petals form a little bowl that concentrates the sun's rays and raises the temperature of the central part of the flower several degrees above the ambient temperature. Thus, keeping its pollinating insects warm and cozy.


United States Distribution Map for Dryas octopetala - White Mountain Avens
Map courtesy of the United States Department of Agriculture Plants Database.

References:

  • Ladyman, J.A.R. Undated. Dryas octopetala: White Mountain Avens. PDF

 

© 2011 Michael Compagno (images) and Rufino Osorio (text) (exclusive of the USDA map).

1 comment:

Anonymous said...

Hello from Alaska. Given the interest in the Younger Dryas and extinction of North American megafauna possibly caused by an extraterrestrial event, your recent post on Dryas octalopetala is most timely. The Mammoth and Mastodon exhibit in Anchorage is ending 1st week of Oct 2011.
From the recent INQUA conference:

http://www.scribd.com/doc/64120238/Abbreviated-YDB-evidence-at-2011-Bern-Switzerland-INQUA-Conference