Wednesday, June 24, 2009
Milkweed flower head (perhaps Desert Milkweed, Asclepidaceae speciosa)
Along the sandhills of Ranch Road 1601
Near Penwell, Texas
Although not rare in these parts, milkweed is not nearly common enough to suit me, and always a delight to find. It's not until you really look at a milkweed's flower head that it becomes something more than an indistinct, tall green weed.
Today my favorite part of the milkweed (tomorrow it may change) is the delicate way the sepals fall steeply down from the flower, then swoop back up, creating, it seems to me, a feminine curve. This is echoed somewhat in the way the leaves grow in this particular species.
Just today at last I realized that the common garden flower, the "butterfly weed" is an orange milkweed, which now makes perfect sense as milkweeds are the sole food of the Monarch Butterfly larva. The toxins in the sap of milkweed -- which some people have a skin reaction to -- are what give the Monarch its foul taste. And protection.
Another thing to admire about the lowly milkweed is the way it distributes its pollen grains. It doesn't just stick it out there for any ol' gust of wind to catch. No, it keeps its pollen in pollen sacs that attach mechanically to insect legs as the fly off, and then has another mechanism that releases the sacs when the insect lands. (This is the same mechanism an orchid uses.)