I should have written a little more about Obolaria in yesterday’s post, which I realized when someone asked a question in the comments.
The thing is, very little is known about this plant. I was able to find one paper* on the subject; in the introduction, the authors state:
Although morphological descriptions of O.virginica exist in various floras (e.g., Radford et al. 1968, Fernald 1970, Wood and Weaver1982, Gleason and Cronquist 1991), information about reproductive capacity or ecological parameters that might influence growth and development is lacking. For example, no information exists about the pollination biology of pennywort, nor have there been any studies to examine basic soil parameters to determine optimal growing conditions of this species.
The paper is interesting, but has no further discussion of pollinators.
I’m not patient enough to sit and watch a stand of Obolaria to see what, if any, insects come to visit. It would be an interesting project, though.
*Notes on the Biology of Obolaria virginica (Gentianaceae) in Southeast Missouri, and the Effects of Leaf Litter on Emergence and Flower Production
Diane L. Wood and Allan J. Bornstein
Department of Biology, Southeast Missouri State University
One University Plaza, Cape Girardeau, Missouri 63701
Do you see any flowers in this photo? They are there, slightly below and to the right of center. You’ll probably have to click on the photo to really see them.
This is pennywort, Obolaria virginica, a species in the Gentianaceae. It grows on the forest floor in deep leaf litter, from Pennsylvania and Ohio south and west as far as eastern Texas. Pennywort has little chlorophyll, so it doesn’t photosynthesize much if at all; instead, it derives energy from a complex relationship with a fungus and a host plant. This relationship is called myco-heterotrophy.
You may find some older sources that describe pennywort as saprophytic, but that concept is obsolete. As I was researching and fact-checking, I came across a great explanation from the USDA Forest Service: What Are Mycotrophic Wildflowers?
The flower color ranges from the medium purple shown here to nearly white, and the thick leaves are more purple than green. Th entire plant stands only a few inches tall.
Thanks to Katie for showing me where to find a good stand of these plants.
I’ve had a lot of fun the last few weeks shooting with the 70-200mm lens and the 105mm macro. A lot of pictures failed (that first lens is a beast if I’m shooting handheld in low light or a breeze), but I enjoy playing with light and shadows and I think I got some decent shots.
wild pinks (Silene caroliniana ssp. pensylvanica)
wild blue phlox (Phlox divaricata)
plantain-leaved pussytoes (Antennaria plantaginifolia)
early meadow rue (Thalictrum dioicum), staminate flowers
smooth rockcress (Boechera laevigata, formerly Arabis laevigata)
early saxifrage (Micranthes virginiensis, formerly Saxifraga virginiensis)
azure bluets (Houstonia caerulea)
leatherwood (Dirca palustris)
lyre-leaved rockcress (Arabidopsis lyrata)
sessile bellwort (Uvularia sessilifolia)
Remember those irises that I obsessed about last summer? One of the stands is located in a vernal pool that’s been dry for two years, but we’ve finally gotten enough rain for the pool to recharge. This will keep me from getting close up shots when they bloom in about a month, but the plants are looking really happy now.
Thanks to LW’s comment on my recent post about toothworts, I was finally able to see a good-sized stand of Cardamine bulbosa, also known as spring cress, bulbous bittercress, or bulbous toothwort.
This species is a wetland obligate; here you can see it almost standing in the water of a vernal pond.
The cauline (stem) leaves are entirely different from the slender and cut-leaved toothworts’.
The basal leaves are, too.
The flowers and inflorescence look much like the toothworts, though. Another Cardamine species found in Maryland, limestone bittercress (C. douglassii), is almost identical to spring cress, but it species has hairy, dark purple sepals rather than the smooth, green sepals seen here.
Spring cress is native to the eastern US, where it ranges from Florida to New Hampshire (where it’s endangered) and into the Great Plains from Texas to Minnesota.