More Magical Milkweeds

Over the past several years I've dedicated a couple of posts to a unique and functionally important group of plants, the milkweeds (Asclepias spp.) (see the past posts here and here).  I've also included milkweeds in several other posts focusing on other topics (see posts here, here, and here).  Based on the number of occurrences on this blog, it's pretty clear that plants in the genus Asclepias are amongst my favorite plants for various reasons, many of which are outlined in the second link above.

Here, I add two additional milkweeds to the collection on this blog: Oval-leaf Milkweed (Asclepias ovalifolia) and Aquatic Milkweed (Asclepias perennis).

Oval-leaf Milkweed (Asclepias ovalifolia)

To begin our June botanical excursion in the Upper Peninsula of Michigan, Brad Slaughter and I stopped to botanize a barrens that was a known location for Oval-leaf Milkweed.  We didn't expect our foray to begin so easily, but as we drove up to the barrens we immediately spotted our target species in the low vegetation before we even exited our vehicles.  In fact, in trying to count (and eventually settling on estimating) the number of individuals, we tallied hundreds more plants than had ever been seen at this location in the past.  This stunning species of the Upper Midwest and Canada is currently listed as endangered in Michigan and Illinois and threatened in Wisconsin.  It is considered a conservative native that grows in dry, coarse soils of prairies, savannas, barrens, and openings in oak woodlands.

Oval-leaf Milkweed (Asclepias ovalifolia)

The leaves of this milkweed are generally oval in shape (hence the specific epithet "ovalifolia") and the entire plant is covered with downy pubescence. The relatively large flowers are creamy white or greenish white with a pinkish hue to the corolla lobes.

Oval-leaf Milkweed (Asclepias ovalifolia) habitat

Growing in a very different habitat and with a more southern distribution is Aquatic Milkweed, a species of swamps, bottomlands, floodplains, and pond margins.  This milkweed is found near the coast in the southeastern United States as well as in a zone following the Mississippi River north from the Gulf of Mexico and the Ohio River east a short distance from its confluence with the Mississippi River, ending in Illinois and Indiana.  I was working in a floodplain in southwest Indiana with Bruce Behan this past July when I came across this attractive species.


Aquatic Milkweed (Asclepias perennis)

The leaves of Aquatic Milkweed taper at both ends, a characteristic that can be used to help distinguish this species from the white-flowered form of Swamp Milkweed (Asclepias incarnata forma albiflora).  In addition, stems of Aquatic Milkweed are often decumbent and rooting at the lower nodes before growing upright.  The flowers, which are smaller than those of Oval-leaf Milkweed, are crisp white, often with a hint of pink (reminiscent of the color of the flowers of Swamp Smartweed [Polygonum hydropiperoides]).

With the recent emphasis on the decline of the Monarch (Danaus plexippus) (see http://www.washingtonpost.com/blogs/wonkblog/wp/2013/12/03/why-are-the-monarch-butterflies-disappearing/), milkweed conservation will likely become an even hotter topic in the near future.  Since Monarchs and milkweeds are large, showy, and charismatic, they have our attention right now, but the problem is much greater than it superficially appears, and extinction will soon take hundreds of other species that are more inconspicuous and that most of us never even realized existed.  A major shift in our conservation and sustainability practices needs to happen now, before it's too late.