Woodland Pinedrops (Pterospora andromedea) ... Carnivorous?

Woodland Pinedrops

Pterospora andromedea

Location: Bandon State Natural Area (BSNA)

Bandon, Oregon

Glandular hairs exude a sticky substance to which small insects adhere.

Primary Inquiry

Do Woodland Pinedrops secrete enzymes that digest insect protein
and incorporate amino acids in their tissue to capture nitrogen?

Is the Woodland Pinedrop carnivorous ... "protocarnivorous"?

by: Keith Franklin Saylor

This plant is the tallest I've observed in BSNA,
measuring almost 90cm (around 3 feet).

Woodland Pinedrops Photo Essay Click on Images to View Larger Photos.

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Fig. 1. In BSNA, Pinedrops are observed generally in open shorepine stands that have the look and feel of a conifer savannah natural feature.	Fig. 2. Pinedrops on the mound beneath shorepine trees.
Fig. 3. Pinedrops corolla flower.	Fig. 4. Pinedrops fruit.
Fig. 5. Pinedrops in situ	Fig. 6. Pinedrops in situ.
Fig. 7. The stalk contains glandular hairs that exude a sticky substance.	Fig. 8. Insects are trapped in the glandular hairs.
Fig. 9. Muliple insects trapped on stem.	Fig. 10.
Fig. 11. Up to 20 insects were counted trapped on one plant with some plants showing 3 or 4.	Fig. 12.
Fig. 13. Insects measured are between 2mm and 5mm.	Fig. 14. Close-up of insect in fig.13.
Fig. 15.	Fig. 16.
Fig. 17. The leaves of the plant also have glandular hairs.	Fig. 18. This insect may be Chilenocaecilius ornatipennis an species not native to the United States.
Fig. 19. The tubular corolla petals have little to no glandual hairs that secrete an adhesive substance; while both are present on the outer margins of the calyx sepals.	Fig. 20. The fruit do not show glandular hairs. However the marginal glandular hairs are present on the calyx. This image shows the petals of the corolla peeling away from the developing fruit.

I have failed finding any scientific documentation showing Pinedrops secrete enzymes that breakdown insect tissue to capture nitrogen (See Inquiry). That is, that they are carnivorous or "protocarnivorous". I have found a discussion in Mountain Wildflowers of the Southern Rockies: Revealing their Natural History by Dunmire and Dobson page 45 which reads: "Pinedrops and other protocarnivorous species have an advantage over other plants in situations where soil nitrogen is scarce. These plants immobilize insects and other small herbivores by trapping them in sticky stem glands and then release enzymes that digest the animal protein and incorporate the amino acids in their tissues. A trapped insect quickly stimulates enzyme secretion, capturing the nitrogen before insectivores steal the prey." This quotation from Dunmire and Dobson is not supported by research or experimental documentation. I wonder whether the writers may be of the opinion that, because other plant species are shown to breakdown insect tissue through substance exuded by glandular hairs, Pinedrops is the same. It is a fair assumption which may be drawn from compelling observational evidence. If anyone is aware of documentation based upon lab based scientific experimentation of whether Pinedrops are carnivorous or protocarnivorous, please comment below with the reference. I will update this document as I find (or made aware of) any documentation. Keith Franklin Saylor kfsaylor@gmail.com

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© by Keith F. Saylor 2025

First Published August 2025

Evernia Prunastri Find in MSU Database

In 2013, I identified a lichen in Michigan's Upper Peninsula that was thought by some to be extirpated from Michigan. The rare lichen is called Evernia Prunastri. I collected a specimen and gave it to the Michigan State University Herbarium where it now resides. Recently, I learned the observation is in the MSU Herbarium Database. Here is a link to the data entry.

https://www.idigbio.org/portal/records/08679521-08f1-4d3d-8d09-95a97ae736c3

Here also is a link to a report I published of the find:

Evernia Prunastri in Michigan

Reflection on my first experience observing nesting northern waterthrush.

Northern Waterthrush Experience

Video shows female gathering nesting material and the nest sight with two egg.

Wet habitat is a beloved haunt; preferably dark and dank wooded wetlands dotted with tree-less fen or bog pockets. Because of this, northern waterthrush and I regularly interacted in the wooded dune/swale complexes along Lake Huron in the northeastern lower peninsula of Michigan.

Nesting season is a favored time of year; not so much the spring and fall migration seasons. I love searching for wild bird nests and observing and experiencing their nest cycle from nest building to young leaving the nest. The northern waterthrush nest eluded me for years.

One day in May 2005,  I sat quietly in a cedar swamp between Squaw Bay and Devils Lake south of Alpena, Mi. I was here before dawn of a mind to watch a ruffed grouse drumming on his drumming log nearby. Dawn approached and I could see him moving around log. Two hours later he was still walking around but had not climbed atop the log to commence drumming. Obviously, he was aware of my presence. This prompted me to move further away. No sooner had I sat down in my new location than a male northern waterthrush began singing. Then, only moments later, a female landed near a moss covered log and began gathering the moss in her beak. Then, she flew away about 30 yards. I lost her in the darkness of the cedar swamp floor.

My heart was pounding. "Just be patient ... wait ... wait ... wait." I told myself. Suddenly she was back gathering more moss. I shifted a bit and brought my binoculars up to try and follow her. Thirty minutes later, after a few more trips to the moss, I had my scope trained on the location she seemed taking the moss. Two hours later I was sure of the spot. Daily, for another 5 days, I watched her from various other locations, with my spotting scope, as she worked to build her nest. Then, she stopped the building activity and I rarely saw her. Although the male was bringing food to her at the nest sight. Two days later I approached the nest and confirmed a nest with two eggs. I observed the nest sight for another month until just before the young left the nest.

Northern Waterthrush Nest with eggs

Evernia prunastri in Michigan - Documentation

Collector Name: Keith F. Saylor

Email: kfsaylor@gmail.com
Species Name: Evernia prunastri

Date Collected: May 26, 2013

State: Michigan

County: Mackinac

Township: Moran Township

Location: Gros Cap Cemetery

Habitat: Human Altered, Cemetery, Ridge along Lake Michigan

Substrate: Bark - Trunk

Host Species: Black Spruce - 80% dead

Height above ground: 3 feet and below from ground

Aspect: North

Evernia Prunastri

Update:August 6th, 2025

Since my observations of E. prunastri in May 2013 many more observations have been posted in the northern lower and upper peninsulas of Michigan on inaturalist.

You may view them by following this link: Evernia prunastri observations in Michigan

Evernia prunastri is commonly found throughout Europe and western United States. It has been documented in the United States midwest, however, it is rare in the midwest.

Lichens of North America on pages 312-313, discussing the abundance of E. prunastri in the Great Lakes region, reads:

"Some very old herbarium species exist from scattered localites in Ontario close to the Great Lakes but the species is almost certainly extinct in that area."

Records from the Global Biodiversity Information Facility show one documented occurrence in Michigan by H.A. Imshaug on August 28, 1961 on the southern end of Beaver Island. 

Dr. Alan Fryday (Michigan State University Herbarium Curator) shared in an email about the status of E. prunastri in Michigan:

In MSC we have 26 Michigan collections of E. prunastri  from 11 counties (Charlevoix, Chippewa, Crawford, Emmet, Keweenaw, Lake, Leelanau, Mackinac, Otsego, Presque Isle & Roscommon). Although the most recent of these collections was made in 1976.

View Evernia Prunastri in Michigan in a larger map

Dr. Fryday also suggested in the same email that, while this lichen is rare in the midwest, the records may under-represent actual abundance.

On May 19th, 2013, I observed Evernia prunastri thallus on spruce trees in the Gros Cap Cemetery west of St. Ignace, Michigan.

Update: The image above was grabbed from google maps on August 6th, 2025. It shows the trees which hosted E. Prunastri have been removed from the cemetery.

These individuals were on dead or dying spruce trees in the cemetery. One specimen was collected and sent to Michigan State University. The collections were made because the dead or dying host trees were within the boundaries of the cemetery representing a hazard to visitors and would soon be cut down.

This image is particularly compelling; it shows Evernia mesomorpha (on the lower left) next to Evernia prunastri just above and to the right. It is not common to see these forms together in most parts of the world.

Documentation:


Location: Gros Cap Cemetery