CHAPTER III - Sandy area and Ragweed (achoo!)

Just south of the parking lot is one of the first stops on a field trip, an open area with very sandy soil. Drummond Sandwort (Arenaria drummondii) and Pointed Phlox (Phlox cuspidata) are sand-loving plants. Anywhere you see sweeps of purple and white you can be sure that the soil is sandy. Texas is thought to be the center of origin for the genus Phlox.

Another sand-dweller is the Dwarf Dandelion, Krigia cespitosa.

 The flowers do look like miniature dandelions. They are closed in the morning and open on sunny afternoons.

Near the trees at the beginning of the walk are some unpleasant members of the Asteraceae. Swamp-weed, also called Marsh-elder (Iva annua) has small, wind- pollinated flowers with highly allergenic pollen. It is very common locally in the fall.

Western Ragweed, Ambrosia psilostachya, is another wind-pollinated composite. It's responsible for much of the fall hayfever problem.


 

The male flowers of ragweed are grouped in little hanging heads at the top of the plant; the female flowers are further down amongst the leaves.
All the yellow structures are anthers, the part of the flower that produces the pollen. Look at all of them! No wonder this plant makes life miserable for allergy sufferers.

Goldenrod (Solidago sp.), which is often blamed, is insect-pollinated and usually not a major allergen.

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 Chapter 4 - Prairies

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