Poisonous to us but popular with birds, Oriental bittersweet (Celastrus orbiculatus) stands out in the landscape now that the leaves are off the trees.

This closeup of the berries shows why we like to use it in floral arrangements.  Very beautiful.

But it’s aggressive.  Imported in 1879 it grows more easily than American bittersweet (Celastrus scandens) with which it hybridizes.  It occurs in nearly every state east of the Mississippi and is listed as invasive from Maine to North Carolina, from Wisconsin to Tennessee.

Watch for small flocks of birds feeding in the woods and you’ll find this vine.  Click here to see what it looks like from a distance.

Bitter and sweet: an unruly competitor that’s food for birds.

(photo by Dianne Machesney)

I happen to like jellied cranberry sauce with Thanksgiving turkey.  How does a native North American fruit end up like this?

It begins with this flower, the Large Cranberry (Vaccinium macrocarpon).

The plants are grown commercially in bogs completely surrounded by dikes.  When the flower becomes a ripened fruit…

…the field is flooded for harvesting.  Harvesting machines, nicknamed “eggbeaters,” knock the berries off the plants. The floating berries are corralled to a conveyor belt.  (This Good Morning, America video shows the cranberry harvest on Cape Cod.)

After the harvest the berries look like this…

They have enough natural pectin that their juice jells on its own if it’s boiled with sugar.

So you could boil them in sugar, strain out the solids, pour the juice in a mold, chill it and voilà.  You have the same jellied cranberry sauce but it doesn’t look like a can.

But really.  I like the magic of a jiggling food shaped exactly like the can it slid from.

A natural fruit in an unnatural shape.

(photo of canned cranberry sauce by busbeytheelder, Creative Commons license. photo of cranberry flower by Dianne Machesney. All other photos from Wikimedia Commons. Click on the images to see their originals)

Take a walk outdoors at this time of year and you’re likely to come home with some of these stuck to your clothing.

These tiny burs are the seed pods of agrimony (Agrimonia eupatoria), a plant native to Europe that was brought to North America for its herbal properties. (See Mark’s comment below! This species doesn’t occur locally but we have similar natives.)

Though the burs look wicked in this close up, they’re actually small and rather weak. Compared to burdock they’re only slightly aggravating.

Click here for a view of a local species (Agrimonia parviflora) when it’s flowering — photos I took at Jennings Prairie last year.

(photo produced using focus stacking, Museum of Toulose, from Wikimedia Commons. Click on the image to see the original)

What are these spiky flowers Charlie Hickey found peeking out of a lake near his home?

Charlie identified them as Eurasian Water-milfoil (Myriophyllum spicatum) an invasive aquatic weed with soft, feathery, submerged leaves that form thick mats in North American lakes. Click on the photo and scroll down to read his description of it.

When I looked further I was amazed to learn that…

• Eurasian Water-milfoil can propagate from a small piece of stem so a little bit caught in the boat propeller in one lake can be carried to another lake and spawn a new invasion.  I saw signs in Maine warning people to clean their boats after they take them out of the water.
• North America has its own native water-milfoil called Northern Water-milfoil (Myriophyllum sibiricum).  The two species can be identified by their leaves but they hybridize and the hybrid inherits characteristics of both.  Very hard to identify.
• The invader is hard to get rid of.  Many techniques have been tried including imported biological controls using a moth, a weevil and a fish.  The fish didn’t work out so well.  It prefers to eat native plants so it denuded the lakes and left the Eurasian water-milfoil for last.
• In the Adirondacks and New England divers remove it by hand every year.  This technique is so successful that according to Wikipedia:  “After only three years of hand harvesting in Saranac Lake the program was able to reduce the amount harvested from over 18 tons to just 800 pounds per year.”

How did water-milfoil get its name?  My guess is that “milfoil” is a contraction of the French “mille feuille” which means “thousands of leaves.”

When it overruns a lake it looks like an invasion of a thousand — no, a million — leaves.

(photo by Charlie Hickey. Click on the image to see the original)

This month Japanese knotweed (Polygonum cuspidatum or Fallopia japonica) is showing off another reason why gardeners imported it.

The flowers have become delicate white seed pods perched above the symmetrical leaves.

Too bad it’s invasive.

(photo by Kate St. John)

These small yellow flowers look innocent, but after they’re fertilized the central disk grows longer and develops into hard, brown seeds.

The seeds splay out as they dry. Each one is topped by a tiny pitchfork of two to four spikes with downward-facing barbs.

The needle-like seeds detach easily from the plant…

… and stick to my sweater.

That’s when I noticed the plant.

The Spanish Needles plant (Bidens bipinnata) is so annoying I was sure it was an alien invasive.  Not!  It’s a native annual that’s very adaptable, willing to grow in disturbed soil in vacant lots.  These seeds grabbed me on Winthrop Street in Oakland.

Bidens bipinnata has many hitchhiker relatives in the Bidens genus.  I identified this one by its lobed leaves and needle-like seeds.

(photos by Kate St. John)

Pumpkins, zucchini, yellow squash, gourds, the members of the Cucurbitaceae family are ripe and ready to eat in North America.

In Pennsylvania’s moist thickets you’ll also find wild and bur cucumbers … but don’t eat them!

Wild cucumber (Echinocystis lobata) is an annual vine that can be unruly at this time of year. After a summer of growing, climbing and blooming it has thrown its tendrils around trees and over bushes.  Its spiny cucumber fruits hang at intervals along the vine waiting to dry out and explode the seeds in all directions.

The seeds take up a big part of the fruit as you can see from this sliced one.   I wonder if any animals eat this…

A look-alike plant with even smaller, spikier fruits is the Bur cucumber (Sicyos angulatus).  Its clustered “cucumbers” aren’t edible and frankly look dangerous because the ratio of spines to fruit is a lot higher.

Newcomb’s Wildflower Guide separates these plants by their flower parts but there are other hints as well:

• Wild cucumber has six petals, Bur has five.
• Wild has smooth stems. Bur has sticky hairs on its stem.
• Wild has deeply lobed leaves. Bur has broad, heart-shaped leaves.
• Wild’s fruits hang separately. Bur’s fruits are in clusters.
• Wild’s fruits are about the size of the leaves (can be 2″). Bur’s fruits are small.

Dianne and Bob Machesney found the wild ones at the Butler-Freeport Trail and burs at Green Cove in Washington County.

If you want to eat a cucumber, go for the real thing in the garden or grocery store.  It’s been cultivated for 3,000 years.

(photos by Dianne Machesney)