This week, I’m featuring Slender Gerardia (Agalinis tenuifolia) as one of our local wildflowers that begins to bloom at this time.
Slender Gerardia is partially parasitic on other plants. Like other members of the genus Agalinis, this species is hemi-parasitic (a plant that is photosynthetic during at least one stage of its life cycle, but still obtains water and nutrients from a host plant) on a variety of hosts (including Gray Goldenrod (Solidago nemoralis) and Wild Strawberry (Fragaria virginiana)), but particularly graminoids (grasses and other herbaceous plants with a grass-like morphology). Slender Gerardia uses haustoria to connect its roots with those of its host plants and then extracts sugars and proteins from that host. In the absence of a host, it grows autotrophically and can complete its lifecycle without a host.
Distinguishing Features:
This plant is an herbaceous annual that grows more or less erect up to 1-2′ tall and usually branches abundantly. The slender stems are rather angular with flat ridges, green to reddish purple, and hairless to mostly hairless. The opposite leaves are up to 3″ long and less than 1/8″ across; they are green to purplish/reddish green, linear, hairless, and stemless with a prominent central vein. Upper leaves have smaller leaflets growing from axils. The slender stem and wiry branches along with the narrow leaves combine to give an overall wispy, airy look to an individual plant.
https://www.minnesotawildflowers.info/flower/slender-leaved-false-foxglove#lboxg-2
Individual flowers and their buds are produced from the axils of the leaves on the upper and outer stems. The swollen flower buds are conspicuously white and resemble floating pearls. Only a few flowers per branch bloom at a time. These open to reveal an interesting flower that is about ½ to ¾” across: 2 petals curl over each other, forming a hood while the 3 lower petals flare out and curve away from the central tunnel. They are tube-shaped and similar in appearance to foxglove, which gives rise to another of its common names, Slender False Foxglove.
The corolla is pink, purplish pink, or medium purple; its 5 rounded lobes are quite large in relation to its tubular base. The lobes have fine hairs along their margins. The lower interior of the corolla has dark purple spots and a pair of faint yellow lines. The slender stems (pedicels) of the flowers are green to reddish purple; they are usually as long or longer than the flowers. Slender Gerardia has the unusual habit of dropping its flowers each afternoon; if you were to visit the same flower that was blooming earlier that day, by early evening, you’ll find the ground around each plant littered with tiny fallen blossoms. There is no noticeable floral scent.
Each flower is replaced by a globoid seed capsule containing many small seeds.
https://www.minnesotawildflowers.info/flower/slender-leaved-false-foxglove#lboxg-3
The wispy foliage darkens to a rich maroon as the season progresses and makes a striking addition to the fall landscape.
Culinary and Medicinal Uses:
There are no known uses of Slender Gerardia as food.
An infusion of the plant has been used in the treatment of diarrhea.
Wildlife Value:
Slender Gerardia attracts a wide variety of pollinators, including ground-nesting bees (such as Small Miner Bee (Pseudopanurgus parvus)), leafcutting bees (such as Flat-tailed Leaf-cutter Bee (Megachile mendica)), long-tongued bees (such as Nimble Ceratina (Ceratina strenua)), Panurgine bees (such as Eastern Miner Bee (Calliopsis andreniformis)), and plasterer bees (such as Eastern Masked Bee, Hylaeus affinis), Slender-faced Masked Bee (Hylaeus leptocephalus), Mesilla Masked Bee (Hylaeus mesillae), and Modest Masked Bee (Hylaeus modestus)). Some Halictid bees collect pollen, while Syrphid flies occasionally feed on the pollen. Among these various insects, the long-tongued bees and Panurgine bees are more effective at cross-pollination of the flowers.
The caterpillars of Common Buckeye (Junonia coenia) feed on the foliage.
Photo Credit: Fritz Flohr Reynolds, https://www.flickr.com/photos/fritzflohrreynolds/15220501015
Mammalian herbivores may browse on the foliage of Slender Gerardia, although it is reportedly toxic to sheep.
Where Found Locally:
Curious By Nature 