The Wild Sensitive Plant,
Chamaecrista nictitans, is an interesting little plant. I had never seen this plant until I found it at Blue Jay Barrens. It was an exciting discovery, as are most discoveries.
It’s not an easy plant to spot. Maximum height is around one foot and the compound leaves easily blend with the surrounding vegetation. The tiny yellow flowers usually hang down from the stem and are hardly noticeable as you walk by.
The leaves of this plant fold up when disturbed, just as with the Sensitive Plant commonly kept as a house plant. The wild plant takes a little more abuse before closing up. The leaf in the lower right of the photo has closed as a result of my touch. I’ve always been fascinated by Sensitive Plants. When I was six, my mother took me along when she visited a friend who had many Sensitive Plants around her house. I got into trouble for going around the house and closing the leaves on all of her plants.
The Wild Sensitive Plant grows in the typical dry open prairie environment and is said to survive in a variety of conditions. At Blue Jay Barrens, these plants are only found in the low pH soils formed over shale bedrock.
Between the base of the leaf and the first set of leaflets is a large, dark colored gland, roughly shaped like a mushroom. The gland secretes a sweet liquid that is highly attractive to insects.
Of course, the insect most likely to exploit such a source is the ant. As they do with other food sources, the ants provide an added level of protection to the plant.
The flat pods of the Wild Sensitive Plant produce about seven to nine seeds. The plant is an annual, so a good crop of seeds is important to its continued survival. Not all seeds germinate their first year. Many remain in the soil and may not germinate for several years. This provides some insurance against a disastrous growing year.
Related to the Wild Sensitive Plant is the Partridge Pea,
Chamaecrista fasciculata. The bloom of the Partridge Pea is much larger and showier. The Partridge Pea is only found at Blue Jay Barrens in the high pH soils formed over limestone.
I call this the middle field, not because it’s in the middle of the property, but because it sits in the middle between the two other recently cropped fields at Blue Jay Barrens. This is also a field of acid soils sitting on shale bedrock. The bulk of the field is a mix of short grasses with many short growing forbs.
Portions of the field were so badly eroded that vegetation still has a problem growing. It’s common to find Reindeer Lichen filling in the voids between the plants.
This is my only low pH field with a short grass component, so I’m always looking for something unusual to show itself here. There’s not a lot of management necessary in this part of the field. If I do anything, it will be to remove a few of the larger cedars.
The field is rather tear drop shaped and as you approach the narrow end, tall grass becomes dominant. Indiangrass is the most common species. Indiangrass readily colonizes new areas and can take over a small area in five to ten years.
This upland edge used to be thick with Multiflora Rose and Autumn Olive. Several years of clearing and herbicide applications have cleaned up that problem and allowed native species to move in. I’m still dealing with many new Rose and Autumn Olive seedlings, but this problem will improve each year.
The next task is to remove the profusion of Japanese Honeysuckle. A couple years of mowing will reduce the amount of honeysuckle, but I’ll eventually need to spray. Honeysuckle stays green into early winter, so it is easy to eradicate by spraying glyphosate in late November when everything else is dormant and immune to the spray.
The problem is that not everything on this site is dormant during the winter. This is Cut-leaved Grape Fern, Botrychium dissectum. These Grape Ferns can be found growing in most parts of the field, but they are particularly abundant beneath the honeysuckle vines. They are short enough to be unharmed by the mower, but even the thickest honeysuckle canopy can’t protect them from the spray. I’m still debating what action to take in dealing with the honeysuckle in situations like this.
Cut-leaved Grape Fern has quite a variable leaf pattern. These deeply dissected leaves are typical of the species, but are the least common leaf form at Blue Jay Barrens. The leaf form I typically find is minimally dissected and sometimes exhibits an almost entire leaf margin. I once thought I had many different species of grape ferns until I discovered what was going on.
There are also several small Blackjack Oaks that I will let remain. This oak seems to have more interactions with prairie invertebrates than any other oak species.
There are Allegheny Mound Ants in the shale based soils, but the mounds are not as numerous here as in the limestone soils. This mound was wreathed by a thick growth of Wild Sensitive Plant.
I don’t know what phenomenon caused the plants to be so thick here. Wild Sensitive Plants have the nectar producing gland at the base of the leaf petiole, but I’ve never seen the large Mound Ants visiting this feature. Perhaps the ants tried to keep the plants cleared from around the mound, but couldn’t keep pace with these rapid growing annuals. I guess this is just one more thing to watch and wonder about.
