Plant pollination has been declining for many reasons including the absence of insects due to pesticides and habitat loss. Now a new reason has surfaced that has nothing to do with the number of flowers and bugs. Research has found that air pollution prevents nighttime pollination by turning off the scent of flowers.
The white-lined sphinx moth (Hyles lineata) is an important nighttime pollinator of purslane, primrose and rose. The research team led by J.K.Chan in eastern Washington, teased out the chemical emitted from pale evening primrose (Oenothera pallida) that attracts the hawkmoths.
The moths were particularly tuned to two different flavors of monoterpenes, a class of chemicals found in plant oils [that] evaporate quickly in the air. Moths, whose antennae are roughly as sensitive as a dog’s nose, can pick up the scent several kilometers away from a flower.
But there is an Achilles heel. When the researchers exposed the monoterpenes to NO3, it reacted with the oils, causing them to degrade by between 67% and 84%.
Air pollution doesn’t just change the scent of flowers. It erases the scent. The moths can’t find them.
Anthropocene Magazine continues, “While NO3 [a component of NOx] is less of a problem during the day because it breaks down in sunlight, it accumulates at night, when many pollinators, including the hawkmoths, are active.”
Afternoon light in Schenley Park, 3 Jan 2024 (photo by Kate St. John)
6 January 2024
Pittsburgh had a rare moment of sunshine on 3 January. I was happy to be outdoors during the Golden Hour in Schenley Park.
This El Niño winter has been so warm that bulbs sprouted in my neighborhood in December. Here are four of the many I found on New Years Eve. That exposed bulb would never have survived in a normal winter like those we used to have just a decade ago.
Flower shoots emerge on New Year’s Eve, 31 Dec 2023 (photo by Kate St. John)
Pittsburgh’s deer won this round.
At Carnegie Museum in Oakland this week I discovered that deer damage near the rear parking lot was so severe that gardeners removed all the Japanese yews. It took two years and an ever-burgeoning deer population to reach this stage.
All the yews have been removed at Carnegie Museum, Pittsburgh, 3 Jan 2024 (photo by Kate St. John)
Last August there were fewer yews than in 2022 because the damaged ones had been removed. Unfortunately the deer were severely browsing the now exposed healthy yews.
Damaged yews at Carnegie Museum in August 2023 (photo by Kate St. John)
Here’s what they looked like in August 2022. Those in front had been eaten bare and died. The next tier was severely browsed and those in back were still normal because the dead and dying yews protected them.
Deer damage on yews at Carnegie Museum, 16 August 2022 (photo by Kate St. John)
The bank of yews could not survive with so many deer.
Over the past week my husband and I traveled to Virginia to visit family, the same trip we made a year ago just as a massive cold front swept across the eastern US. Last year temperatures dipped to 13 degrees F in Virginia. This year the weather was mild in the upper 40s to low 60s. The temperature made a difference in how many birds I saw on the trip. Believe it or not there were fewer birds in mild weather!
For instance, on both trips I visited Back Bay National Wildlife Refuge. In 2022 it was well below freezing yet I saw 29 species including thousands of waterfowl: Canada geese, 250-300 tundra swans, gadwall, wigeons, black ducks, ring-necked ducks, scaup, ruddy ducks, and coots (see checklist here).
This year I saw only 18 species and the water birds were reduced to literally a handful each of Canada geese (heard), tundra swans (heard), gadwall and pied-billed grebes (checklist here). Meanwhile the most abundant species was 40-50+ yellow-rumped warblers feasting on myrtle berries.
Abundant myrtle berries attracted yellow-rumped warblers at Back Bay NWR (photo by Kate St. John)
This year’s El Niño is has certainly affected the birds. On the East Coast it is warm enough that many don’t have to come south to find food.
Will temperature make a difference during today’s Pittsburgh Christmas Bird Count? I suspect precipitation will have a larger affect. There’s a 90% chance of snow showers and then rain. 🙁
If you’ve only seen Jack O’Lantern mushrooms (Omphalotus olearius) during the day you may have thought they were named for their orange pumpkin-like color.
Jack O’Lantern mushrooms, Schenley Park, 30 Sept 2018 (photo by Kate St. John)
Instead they are aptly named because they glow green in the dark, as shown in the top photo.
Perhaps, like Armillaria mushrooms, Omphalotus olearius is bioluminescent because of the chemical reaction they use to consume decaying wood. Armillaria‘s chemical reaction glow is described in this vintage article on foxfire.
Honeybee on asters, Schenley Park, 28 Sept 2023 (photo by Kate St. John)
7 October 2023
The best photos from this week have been published already (Yesterday at Hays Woods Bird Banding) so I’m reaching back to late September for a few of things I’ve seen.
Bees of all kinds are attracted to deep purple asters beside the Westinghouse Memorial pond in Schenley Park. The honeybee, above, is hard to see near the flower’s orange center.
At Duck Hollow, yellow jewelweed still has flowers as well as fat seed pods. Try to pull one of the pods from the stem and see what happens.
Yellow jewelweed flower and seeds, Duck Hollow, 26 Sept 2023 (photo by Kate St. John)
On 28 September I explored the slag heap flats near Swisshelm Park where (I think) solar arrays will be installed. Because the slag is porous the flats are a dry grass/scrub land where this shrub would have done well except that it’s been over-browsed by too many deer. It looks like bonsai.
Deer damage at the future site of solar flats, NMR Valley, 28 Sept 2023 (photo by Kate St. John)
Deer overpopulation is also evident by the browse line at the edge of the flats.
Browse line at the edge of the future solar flats,NMR Valley, 28 Sept 2023 (photo by Kate St. John)
On 26 September at Duck Hollow I encountered an optical illusion where Nine Mile Run empties into the Monongahela River. It looks as if this downed, waterlogged tree is damming the creek and that the water is lower on the downriver side of it. This illusion seems to be caused by the smooth water surface on one side of the log.
Optical illusion: the log is damming Nine Mile Run, 26 Sept 2023 (photo by Kate St. John)
We found a tiny red centipede crossing the trail at Frick Park on 30 September …
Tiny red centipede, Frick Park, 30 Sept 2023 (photo by Kate St. John)
… and a puffball mushroom outside the Dog Park.
Puffball mushroom, Frick Park, 30 Sept 2023 (photo by Kate St. John)
On 27 September hundreds, if not thousands, of crows gathered at dusk near Neville Street in Shadyside before flying to the roost. I thought this would happen again the next day but they changed their plan and have not come this close again.
Hundreds of crows take off from a roof on Neville Street, 27 Sept 2023 (photo by Kate St. John)
Sometimes sunrise is the most beautiful part of the day.
Sunrise at Neville Street, 28 Sept 2023 (photo by Kate St. John)
These photos don’t give the impression that it’s been abnormally dry, but precipitation in Pittsburgh is down 6″ for the year. Almost 2″ of that deficit occurred in September. The Fall Color Prediction says our leaf color-change is later than usual.
In September birders lurk near devil’s walking stick in Frick Park because the plants attract birds on migration. Crawling with tiny insects and full of fruit, devil’s walking stick is often swarmed with visiting warblers, cedar waxwings and robins. But is it really devil’s walking stick (Aralia spinosa)? Or is it the invasive look-alike Japanese angelica (Aralia elata)? Or even worse, is it a hybrid?
Anne Swaim responded to Dave’s post saying “Probably Aralia elata, the Japanese Angelica. Great bird attractant (but really invasive.) Same genus as the native Devil’s walking stick.”
Native to eastern Russia, China, Korea and Japan, Japanese angelica (Aralia elata) was brought to the U.S. as an ornamental plant. It’s well known in eastern Pennsylvania and New York state because those areas are outside Aralia spinosa‘s native range. Pittsburgh is on the border though, so I always assumed I was looking at the native plant.
It’s so hard to tell them apart that New York Botanical Garden posted this guide to invasive look-alikes. Here’s a screenshot from the Aralia sp pages:
Their Quick ID is helpful for non-botanists like me.
Quick ID of Aralia elata (invasive alien):
Leaf veins: Main lateral veins running all the way to the tips of teeth at the leaf margin.
Inflorescence: Inflorescence shorter, typically 30–60 cm long, and WITHOUT a distinct central axis (often wider than long, with base usually surrounded by and even overtopped by foliage).
Quick ID of Aralia spinosa (native):
Leaf veins: Main lateral veins branching and diminishing in size before reaching the leaf margin (smaller branching veins may run to the tips of teeth)
Inflorescence: Inflorescence longer, often 1–1.2 m long, WITH a distinct central axis (typically longer than wide, base usually elevated above foliage).
I tried to identify the plants at Frick by looking at the leaves but it’s very hard to do. The easiest way is by looking at the inflorescence — the tower of flowers.
Japanese angelica’s (Aralia elata) inflorescence basically lies flat. It does not have a central stem and the leaves may cover some of the flowers. Here’s Japanese angelica at Frick.
Inflorescence below the leaves = Japanese elata in Frick Park (photo by Kate St. John)
Devil’s walking stick’s (Aralia spinosa) inflorescence stands tall above the leaves on a central stalk.
Meanwhile, for the sake of the warblers I am deciding not to get excited that these plants are alien. The birds love them so much and I love the birds so …
Pilewort seeds blow away in the wind, 20 Sep 2023 (photo by Kate St. John)
25 September 2023
Have you seen white fluff blowing in the wind lately? The fluff is not from dandelions. At this time of year it’s from pilewort.
Pilewort (Erechtites hieraciifolius) is a native plant in the Aster family that looks very weedy, even ugly. At two to eight feet tall the flower heads on the tips of the branches look like seed pods because they barely open to expose pistils and stamens. To appreciate the flower you need a magnifying glass. Its beauty is microscopic.
It doesn’t take much wind to set it going. Do you see the flying fluff in this closeup? Look for the tiny yellow arrow in this photo and the one at top.
Pilewort near Phipps’ parking lot, 20 Sep 2023 (photo by Kate St. John)
Why is it called pilewort? The common name literally means “hemorrhoid plant.” Penn State Extension explains.
Native Americans used American burnweed [pilewort] to treat rashes caused by exposure to poison ivy and poison sumac. Medicinally, it has also been used as an emetic and to treat dysentery, eczema, diarrhea, and hemorrhoids. It has been used to create a blue dye for wool and cotton and, despite its intense flavor, can be eaten raw or cooked.
Pileweed’s other common name is American burnweed because it grows easily after brush fires. It loves disturbed soil and is easy to find by the side of the road, in churned up gardens, and in urban areas. In this age of bulldozers, roto-tillers and garden digging, pilewort has many opportunities to germinate.
I found a lot of it at Duck Hollow.
Pilewort at Duck Hollow, 18 Sep 2023 (photo by Kate St. John)Pilewort at Duck Hollow, 18 Sep 2023 (photo by Kate St. John)
Perhaps it’s a good thing that pilewort grows prolifically. A 2002 study in Japan found that Erechtites hieraciifolius is good at absorbing the greenhouse gas, nitrogen dioxide, turning it into an organic form.
It may not be beautiful but pilewort plants itself by the side of the road and then cleans the air.
Purple milkwort, Sewickley Heights Park, 8 Sept 2023 (photo by Kate St. John)
12 September 2023
Why do some plants have the suffix “-wort” in their names?
The suffix “-wort” simply means “plant.” In earlier centuries, plant common names often referred to physical characteristics, resemblance, or recommended medicinal uses.
Purple milkwort (Polygala sanguinea), above, is native to North America. “The genus name Polygala comes from the ancient Greek “much milk”, as the plant was thought to increase milk yields in cattle.” I have no idea if this works.
Mugwort (Artemisia vulgaris), related to ragweed, is used in cooking and has been used medicinally. It has a bitter flavor. Why “mug”? I don’t know.
Mugwort leaves are white underneath (photo by Kate St. John)Mugwort flowers are brown in September, Schenley Park, 23 Sept 2021 (photo by Kate St. John)
Pilewort (Erechtites hieraciifolius) is a member of the Aster family that grows easily in disturbed soil. Quirky Science says the “reported uses include the treating of hemorrhage, dysentery, skin diseases, and cholera. It is a purgative and emetic. The name suggests it is good in treating piles (hemorrhoids).”
Pilewort, Pittsburgh East End, 28 Aug 2023 (photo by Kate St. John) Pilewort flower heads and seeds, Sept 2016 (photo by Kate St. John)
St. Johns wort (Hypericum perforatum), imported from Europe, is so-named because it blooms in June and was traditionally harvested on St. John’s Day, June 24, to adorn homes and ward off evil. It is an herbal treatment for depression and has been planted nearly worldwide.
St. Johns wort, South Side of Pittsburgh, July 2022 (photo by Kate St. John)
Turtleheads blooming in Schenley Park, 3 Sept 2023 (photo by Kate St. John)
9 September 2023
Seen this week:
Turtleheads and late boneset flowers at Schenley Park. Do you see the honeybee?
Honeybee flies to late boneset, Schenley Park, 4 Sept 2023 (photo by Kate St. John)
A rainbow with crows over Oakland.
Rainbow over Shadyside on 7 Sept 2023 (photo by Kate St. John)
Fiery sunset on 7 September.
Fiery sunset on 7 Sept 2023 (photo by Kate St. John)
Six deer in Schenley Park — only 5 made it into the photo.
Five of six does in Schenley Park along the Bridle Trail, 4 Sept 2023 (photo by Kate St. John)
But there’s a photo of deer I wish I’d been able to take: Friday morning 8 September along 5th Ave between the Cathedral of Learning and Clapp Hall I saw 3 deer — 2 does and 1 fawn — standing on the pavement at Clapp Hall. They were close to the curb of 5th Ave at Tennyson as they tried to figure out how to cross 5th Ave during rush hour.
Beefsteak plant, Lancaster County, September 2022 (photo by Kate St. John)
Here’s a pretty plant, an invasive alien, that I’ve not seen in Pittsburgh but is easy to find in Lancaster County, PA where I took this picture.
Beefsteak plant (Perilla frutescens) is a member of the mint family native to Southeast Asia and the Indian highlands and is grown as a crop for Japanese, Korean and Chinese cuisine. Its common names include shiso and Korean perilla. The “beefsteak” name was coined because the darkest varieties have leaves as red as meat. The wild plants I saw in Lancaster County had green leaves and dark red stems.
Perilla frutescens is widely cultivated in Asia as an edible plant but it has downsides including contact dermatitis from touching the leaves and anaphylaxis after consuming a large amount of seeds. Those who cultivate it know what to do but the rest of us should be cautious.
Brought to the U.S. as an ornamental beefsteak plant escaped to the wild and is now invasive in six states from Pennsylvania to Tennessee. The plant is always toxic to cattle, horses and other ruminants including white-tailed deer.
