Monday, July 25, 2011

Sassafras Arching Trunks

Trees such as sourwood, black gum, and river birch often having a pronounced bend to their trunks. I've always assumed that it is a phototrophic response whereby the stems are simply growing towards the area where light is most readily available. But in the Sassafras trees growing in our home landscape (Clemson) something else seems to be going on. In the last 5 years or so there have been two years in which the female trees have had a super abundant fruit crop and the weight of all those developing fruits caused the stems to bend downward during the several weeks that the fruits matured. These periodic heavy fruit loads, I believe, contribute to the permanent bend often seen in Sassafras trunks. Additional support for this hypothesis is that male trees, which lack the burden of producing weighty fruits, generally have much straighter trunks than do the females, at least in our landscape. It would be interesting to see if this pattern holds true for Sassafras "in the wild".

Sunday, July 10, 2011

Black cohosh

Black cohosh (Actaea racemosa) is currently in flower off the Blue Ridge Parkway. It's easily recognizable by its 3-8 ft tall flower stalks with tassel-like white flowers and coarsely toothed leaflets. The fetid smelling flowers attract carrion flies and beetles which function as pollinators. In a pinch, you can rub the flowers on your exposed skin to ward off mosquitoes; however, in so doing you may attract carrion flies and beetles which think you're dead meat (not to worry, they don't bite).

Monday, May 30, 2011

Fire pink (Silene virginica)

Fire pink (Silene virginica) tends to be restricted to relatively open areas (such as rocky slopes with shallow soils) as it is a poor competitor. So, if you add this plant to your garden, you'll want to prevent neighboring plants from getting too close and overtopping it.

Fire pink is a classic hummingbird-pollinated plant as it has tubular red flowers with abundant nectar, no landing platforms (as is typically found in bee or butterfly-pollinated plants) and no detectable floral odor. The flowers depend on hummingbirds to transfer pollen from the anthers of one flower to the stigma of another for successful fruit and seed production.


Mountain laurel


Mountain laurel (Kalmia latifolia) is currently in flower off the Blue Ridge Parkway in the mountains of North Carolina. Look for the white to pink bowl shaped flowers in dense showy clusters. While plants can be found both in open sunny areas and in shaded sites under a forest canopy, it's those plants that receive more sunlight that flower most prolifically.

Friday, May 20, 2011

Beargrass in flower

Beargrass (Yucca filamentosa) is now in flower in dry open woodlands, on rock outcrops, and along roadsides in the piedmont and mountains. For fruits to form, this plant requires the pollination services of a tiny moth (the Yucca moth). Unlike all but a few pollinators, the Yucca moth intentionally pollinates the flowers. After pollinating a flower, a female moth lays eggs in the ovary, the larvae hatch, and then feed on the developing seeds. Usually about 30 % of the developing seeds are eaten. In this plant-insect mutualism, the flowers get pollinated and the moth is rewarded not by pollen or by nectar (the usual floral rewards) but by seeds for its larvae. Look for the tiny cream-colored moths hanging out in the flowers during the day.

Monday, May 2, 2011

Listen to Rudy Mancke discuss my new wildflower book

Rudy Mancke did a nice audio piece on Nature Notes about Wildflowers and Plant Communities of the Southern Appalachian Mountains and Piedmont, UNC Press.

Wildflower pilgrimage

I had the opportunity to participate in the wildflower and bird pilgrimage in Asheville, NC the last weekend in April. It was wonderful! There were hikes in the woods, abundant wildflowers, and interesting people to share the fun. Yellow lady's slipper (Cypripedium parviflorum) was just one of the many species we saw in bloom in the southern Appalachian mountains.