11 August 2022
For 24 days — 5-29 August 2022 — a team of goats and their guard donkey from Allegheny Goatscape are back in Frick Park eating invasive plants.
One of their targets is invasive mile-a-minute (Persicaria perfoliata). It has thorns all over it …
.. but the goats eat it anyway. The challenge will be: Can they eat it fast enough?
Learn how mile-a-minute got to North America in the article below. Pennsylvania is involved!
(photos by Kate St. John)
10 August 2022
Sometime this summer the Department of Public Works placed a large sandstone rock at the base of the stairs behind the Schenley Park Visitors’ Center. The prominent fossil facing the stairs tells a story about life in Pittsburgh 300 to 330 million years ago.
During the late Carboniferous period, while this rock was still sand, a Lepidodendron tree fell on it. Lepidodendron had scales on its branches and trunk that left impressions in the sand, illustrated below in increasingly fine detail.
The sand became sandstone and in the early 21st century the rock separated from its fellows thereby exposing the fossil. This rock many have fallen at the Bridle Trail rockslide.
I have never seen Lepidodendron’s closest living relative, Lycopodium, in Schenley Park …
… but I’ll look for it now that I’ve seen its fossil ancestor.
Thank you to Public Works for placing this fossil rock on display in Schenley Park.
p.s. If this Lepidodendron had fallen in a swamp instead of on a sandy beach, it would have become coal. Read about similar fossils at Ferncliff Peninsula in Ohiopyle State Park in this vintage article: Fossils at Ferncliff
(photos by Kate St. John, illustrations from Wikimedia Commons; click on the captions to see the originals)
6 August 2022
By early August many flowers have already produced seeds. Wingstem (Verbesina alternifolia) above displays every step in the process: buds, new flowers, fading flowers and seed packets.
The three-flanged seed pods of American wild yamroot (Dioscorea villosa) are as distinctive as its pleated leaves.
Greater celandine (Chelidonium majus) now has both seed pods and flowers (seeds in shadow at left). This alien plant is easy to find in Schenley Park because it is toxic to deer.
Yellow jewelweed (Impatiens pallida) is much harder to find because it is ravaged by the large deer herd.
If this flower evades the deer it will turn into a seed pod that bursts explosively when ripe.
(photos by Kate St. John)
4 August 2022
By the end of July in western Pennsylvania, there are patches of orange string draped over plants in moist locations on the edge of the forest. The orange strings are dodder (Cuscata), a native annual parasitic vine that blooms from July to October.
Dodder wraps itself around its host and inserts tiny haustoria to suck out water and nutrients. Last week I found it parasitizing invasive porcelain berry — Go, dodder! — but dodder won’t beat back the grapevine. Dodder doesn’t kill its host.
Look very closely and you can the haustoria clinging and dodder’s tiny flowers that are pollinated by wasps.
Dodder will die at the end of the growing season yet you may find it in the same spot every year. Find out why this happens and other interesting tidbits in this vintage article.
(photos by Kate St. John and Esther Allen)
2 August 2022
This flower head is so spiny and eye catching that we rarely look at the leaves though they’ve been studied intensely at least three times since the 1870s.
Teasel’s (Dipsacus fullonum) paired perfoliate leaves collect rainwater in the cup where they clasp the stem and unwary insects drown in the puddle. Notice the water in the leaf cups below. (Click the first photo to see a marked-up version showing the water line.)
In the mid 1870s Francis Darwin, son of Charles Darwin, hypothesized that teasel digests the decaying insects, then studied and published about the digestive mechanism. Not everyone was convinced. Teasels were studied again and again.
A 2011 study published in PLOS ONE found that teasels with dead insects in the leaf cups set more seed than those without, thus a nutrient benefit of carnivory. But a 2019 study in Canadian Science Publishing found that seed production had more to do with soil nutrients.
Teasels obviously use spines to defend themselves, but do they play offense, too? Are they carnivorous? It would be nice to think so but we don’t know.
Read more in this 2017 article In Defense of Plants, published before the 2019 study.
(photos by Kate St. John and from Wikimedia Commons)
30 July 2022
Wrapping up July …
St. John’s wort’s yellow flowers always attract my attention because the plant shares my name. Find out what’s in the name in this vintage article from 2012.
This month I learned that chicory flowers (Cichorium sp) last only one day. On a foggy morning I found this one, barely open and doomed to wilt by afternoon. Learn more at #bioPGH Blog: Chicory, Dickory, Dock – The Flowers are on the Clock.
We had several spectacular sunrises in July, especially this on the 17th.
Soon we’ll say good morning to August.
(photos by Kate St. John)
23 July 2022
The flowers on Queen Anne’s lace (Daucus carota), or wild carrot, are so lacy and regular that they resemble snowflakes when viewed from above, especially in black-and-white.
Look closely and you’ll see that the tiny flowers inside the umbel have 5 regular parts. Step back to see the pattern of 5’s replicating to the edge.
Unlike winter’s 6-sided snowflakes (below) these summer “snowflakes” have only five.
p.s. See Vicki Dinsmore’s comment below about wild parsnip which is not the same thing!
(photos by Kate St. John and from Alexey Kljatov via Wikimedia Commons)
16 July 2022
Flowers are blooming, fruits are ripening and the sky has been spectacular. Here are just a few things seen outdoors this week and last.
(photos by Kate St. John)
2 July 2022
Seen this week at Duck Hollow, listed in photo order:
I heard ravens calling in the distance while I took these pictures. Woo hoo!
(photos by Kate St. John)
25 June 2022
This week was pleasant, then hot, and always buggy in the woods. A few flowers were blooming and berries are ripening.
Click on the image below to see a photo of the entire rock.
Click on the fruit photo below to see the branch where this mulberry came from in Frick Park.
(photos by Kate St. John)