Tuesday, April 18, 2017

Flocks of Phlox

Ozark Downy Phlox - Phlox pilosa
Linda Ellis MN came to the Wildflower Walk on April 1st with an additional mission.  She was serving as our visiting botanist but also was looking for a particular wildflower.  I will let her explain.

"A friend in the native plant nursery trade recently asked me to look for plants of Ozark downy phlox (Phlox pilosa var. ozarkana) so seed could be collected. I had really never studied the different expressions of phlox species before. That led to some research and some intense field study and photography of the phlox plants at Bull Creek on our Master Naturalist Wildflower Walk last weekend."

Pubescence- Click to enlarge
Phlox species can be either annual or perennial and come in a variety of colors including rose, red-purple, lavender, all white or white with a purple center. In our search of the ozarkana variety, we were looking for plants with wide, paired leaves with a somewhat heart-shaped base.  Most importantly, the leaves, stems and calyxes needed to be covered with glandular hairs as opposed to plain hairs. We found plants with glandular hairs and wide leaves in the valley and collected some for magnification.

Microscopic examination clearly showed the glandular pubescence we were looking for.

Linda's explanation peaked my curiosity.  "Pubescence" is defined as "soft down or fine short hairs on the leaves and stems of plants or on various parts of animals, especially insects."  It required a hand lens to identify it, unlike the other definition, "the time when puberty begins," which was a little more obvious.  Since our children are around 50 we don't need to think about that any longer.  Clicking on the photograph on the right will give you the chance to enlarge it as Barb was doing above.

Glandular hairs - REK
Trichome is a term that covers all these hairs, whether on plants, algae, or lichens.  They can serve many functions such as discouraging small herbivores, providing a barrier to frost formation, reflecting sunlight and deflecting wind to reduce moisture loss through transpiration.

Glandular trichomes produce some kind of secretion such as essential oils such as those in mint plants.  In some species such as carnivorous plants, they produce glue like substances to capture insects.

They can also capture the interest of an easily distractable naturalist.  I spent more time that I would like to admit photographing these beauties under the microscope.

Some other finds from the April 1st Wildflower Walk are in this album.

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