Thistle Plants

An early-stage thistle plant.

An early-stage thistle plant.

In previous posts, I have shown several pictures of Nodding Thistle (Carduus nutans) flowers, so I thought it was about time I showed a photograph or two of the plant itself. All the pictures of Nodding Thistle that I have posted so far came from the plant shown in the photograph above. It was growing along a road near our house. The plant had only early-stage flowers when this photograph was taken in May. Later the plant produced mature flowers, but shortly after that the county road mowers got it. I had to use other plants to get plants with mature seeds (see the a subsequent post for these).

Prickles on a thistle plant

Prickles on a thistle plant

The photograph above shows more detail of the rather impressive prickles growing on the stem and leaves.  No wonder livestock are reluctant to graze on it!

 

Phinizy Skimmer

 

A male Great Blue Skimmer

A male Great Blue Skimmer

My brother and his wife visited us earlier this summer, and we went to the Phinizy Swamp Nature Park in Augusta, Georgia. On previous visits my wife and I had seen a variety of wildlife, including fish, snakes, aquatic insects, and lots of birds. This time, however, there was very little water along the boardwalk across the swampy area. So we did not see much of the larger types of wildlife that we had hoped to see.

However, if one looks closely, there is always something interesting to see. There were several dragonflies perched on vegetation along the boardwalk. The one pictured here is a Great Blue
Skimmer (Libellula vibrans). It shows the blue-green eyes and white face that is typical of the species. It was quite unafraid and remained calm while I took these photographs. This one is a male; females look quite different. They lack the blue surface coating seen on the male; they have a yellow and brown pattern on the abdomen. Very old females may become dark-colored, but should always show some of the yellow and brown on their abdomen.Head on view of a Great Blue Skimmer

Head on view of a Great Blue Skimmer

Thistle Flowers

A couple of posts back I published a composite photograph of a flower head of Nodding Thistle (Carduus nutans)  It is such a photogenic species, I decided to add some more photographs.

Side view of a Nodding Thistle Head.

Side view of a Nodding Thistle Head.

View from above a Nodding Thistle Head.

View from above a Nodding Thistle Head.

Remember that this species is in the family Asteraceae , so what you are seeing here is a “head” containing hundreds of individual small flowers. Some members of this family have two types of flowers in their head. See my earlier post on Oxeye Daisies (http://www.gkochert.com/fibonacci-flowers/) if you need to refresh your memory about this. Thistles like this one have only one type of flower… ray flowers. This view from above shows various stages in the maturation of the flowers. The most immature flowers are the white structures in the center. As you progress away from the center you see increasingly mature flowers; those around the very edge of the flower head are the most mature.

In the next post I will show the plant itself.

Ghost Tents

A Tent Caterpillar Ghost.

A Tent Caterpillar Ghost.

How about this…is it some sort of ghost in the woods? Rather more mundane I am afraid. It is the web made by a colony of Tent Caterpillars (Malacosoma americanum). This has been an unusually fruitful year for many sorts of plants and animals around here, and the Tent Caterpillars are no exception. This set of photographs was taken along a short stretch of highway just north of our house.

Tent Caterpillarwebs along a highway.

Tent Caterpillarwebs along a highway.

I have included a highway sign in the photograph above to give some idea of the scale of these webs. There were hundreds of feet of webs like these along the road we traveled.

A colony of Tent Caterpillars.

A colony of Tent Caterpillars.

Here is a closer view of one colony. The individual caterpillars can be seen in masses inside the web. They normally stay inside the web for protection during the hotter part of the daylight hours, then come out at night, early morning or early evening to feed on adjacent foliage. They make a trail of silk as they move along branches toward edible leaves. Some pheromones are also deposited along the silk trails, and other members of the colony follow these trails to food sources. One caterpillar can recruit the entire colony to follow it to a new plentiful food source.

Tent Caterpillars are subject to predation by tachinid flies and various sorts of parasitic wasps. When one or more members of the colony detects such a predator, they signal in some way and all the members of the colony may begin to thrash about, thus giving a moving target to the fly or wasp and reducing its ability to oviposit on the caterpillars.

The caterpillars are apparently quite distasteful. If their diet contains wild cherry leaves, which contain cyanide linked to carbohydrates, they are able to store the cyanide in their bodies without harm to themselves. However, when threatened they are able to regurgitate cyanide-containing fluids which deter many potential predators.

When I was a kid, we used to use Catalpa Worms (Ceratomia catalpae)  for fish bait when we could get them. But there were not many Catalpa Trees (Catalpa sp.) around. So we got the bright idea of using Tent Caterpillars for fish bait. There were plenty of these around, even if they were messy to collect. I don’t know if it was cyanogenic saliva or what, but no fish would bite on them at all.

The only birds that are known to eat Tent Caterpillars are cuckoos, both Yellow-Billed Cuckoos (Coccyzus americanus) and Black-Billed Cuckoos (Coccyzus erythropthalmus).

Tent Caterpillars showing host specificity.

Tent Caterpillars showing host specificity.

Another thing that is notable about Tent Caterpillars is there preference for certain tree species. This photograph shows one tree heavily infested but adjacent trees and shrubs are untouched. Tent Caterpillars seem to prefer trees in the Rose family (Rosaceae)s such as Cherry and Apple for deposition of eggs.

Tent Caterpillars are generally regarded as pests. They are deemed unsightly in themselves, and they certainly can defoliate a tree in short order. My grandfather used to get rid of them by tying a rag onto a long pole, soaking the rag in kerosene, lighting it up and burning the webs and their inhabitants. This performance was eagerly observed by us when we were young.

Coots

 

American Coots

American Coots

I really like American Coots (Fulica americana), also called Common Moorhens. There always seems to be lots of them around, and they are fun to watch. This group was busy diving for aquatic vegetation, and you can see the droplets of water on their waterproof feathers. A couple of them even have some vegetation dangling from there beaks.

I have tried to investigate the origin of the word “coot” without much success. Dictionaries always list two meanings…one meaning refers to the bird and the other usage is for a cantankerous person, usually an older one. I myself have been addressed as an “old coot”.

 

Nodding Thistle

Nodding Thistle flower heads.

Nodding Thistle flower heads.

Here is a composite shot of a Musk Thistle also known as Nodding Thistle (Carduus nutans). You can see the single flower head that I started with down below.

A single flower head of Nodding Thistle.

A single flower head of Nodding Thistle.

Quite attractive, but I can understand why it is not universally admired, and it is in fact classified as a noxious weed in many places all over the world. This particular plant was growing along a roadside a couple of miles north of our house. Roadsides, neglected places, and  pastures are common habitats for this immigrant from Eurasia. It produces prodigious quantities of seeds. Various numbers are published in the literature, but under good conditions more than 100,000 wind-dispersed seeds may be produced by one plant. So it spreads rapidly to cover entire pastures. Nothing seems to eat it (including native wildlife or livestock) or cause it any disease problems. This condition is common with plants that are introduced from other places, either accidentally or on purpose…none of the insects or diseases that keep them in control in their native habitats are introduced with them. Similar accidental introductions include kudzu, adelgids (insects that are now killing all our native red spruce and hemlock trees), the chestnut blight that played havoc with our chestnut trees and many other examples.

Two insects which attack thistles in Europe (the Thistlehead-feeding Weevil (Rhinocyllus conicus) and the Rosette Weevil (Trichosirocalus horridus) have been released in the U.S. in hopes of providing some biological control. What would you guess happened? The insects did, indeed, eat some Nodding Thistle. But they are also eating some of our native, non-problem thistles, including some rare species we would like to keep around. This is reminiscent of the introduction of the mongoose to Caribbean Islands to control poisonous snakes. The mongoose found it easier to eat the native birds than the snakes!

Back to this thistle…the flower heads are typically borne singly on branches that bend over (droop or nod) a few degrees, hence the common name Nodding Thistle. It is in the family Asteracee (Composites) which also includes familiar plants such as sunflower and daisy. What you are seeing in the center part of the flowering “head” is 50 or more tiny flowers, each of which produces one seed. The group of flowers is surrounded by some formidable spines. The stalks and leaves are also full of spines, so it is difficult to handle or for any grazing animal to eat.

More about this thistle in the next post or two…

Chanterelle Anyone?

A Chanterelle Mushroom

A Chanterelle Mushroom

Here is a welcome sight. This is a Chanterelle (Cantharellus cibarius) mushroom, one of the most distinctive and delicious of our native mushrooms. Cantharellus means “drinking cup” and cibarus comes from a Latin word for food. So the scientific name can be translated as “a little drinking cup that you can eat”.

This year lots of Chanterelles have appeared in our woods, and it was easy to collect enough for a meal. They are reasonably easy to identify and collect. Their bright yellow-orange color and their trumpet-like shape stand out. They are really easy to spot against the brown color of the leaf litter. In addition, they have ridges on the underside rather than the gills characteristic of most mushrooms. These ridges divide and subdivide, but it is clear that they are not gills.

We have lived in our present location for a little more than 20 years, but Chanterelles have appeared only sporadically. The last time they were present was about four years ago. They seem to be associated with unusually rainy Spring seasons, but there may be other contributing factors. Chanterelles are mycorrhizal with certain types of trees, so they tend to appear in the same locations time after time. (Mycorrhizal means they interact with small roots of plants, usually trees.) Filaments of the fungus wrap around the tree rootlets and the two organisms interact in a way that is beneficial to both. The trees provides water and nutrients to the fungus, and the fungus helps the tree to absorb minerals from the soil. The fungus may also provide some disease resistance to the tree.) Mycorrhizal fungi, such as the Chanterelle, cannot grow without their host tree, so Chanterelles cannot be grown in culture. They must be collected from the wild, and are very expensive to buy on the open market.

The standard warning applies. Do not consume any wild mushroom unless you are absolutely sure of its identity! There are many poisonous species out there, some of which could be easily mistaken for a Chanterelle,