Announcements of interest to Ramblers:
Pie day!!! Please come!!!
Sandy Creek Nature Center 40th Anniversary Celebration
Sunday, September 29, 2013; 3PM to 5PM
Trail walk with Dan Williams!
Sandy Creek Nature Center
Tuesday, October 1, 2013; 9:00AM
Photos of today's ramble are courtesy of Don Hunter (the complete set can be found here.)
Today's Ramble began with Catherine Chastain reading a selection from a wonderfully illustrated book, Middlewood Journal: Drawing Inspiration from Nature by Helen Scott Correll, p. 78:
I can tell summer is losing its grip. It’s interesting to note that I understand more every year that the seasons, which I used to consider fairly distinct, are really quite blurred. Cat brier and Virginia creeper leaves begin turning red as early as July: fuzzy spring-like oak leaves sprout until frost. During this morning’s ramble I saw the first “fall” silvery aster bloom for the year, and the grass-leaved and golden asters, which have been blooming for a couple weeks. Thoroughworts (upland, round-leaved, and hyssop-leaved) are in bloom, but fading. Tall goldenrods already brighten the woodland edges. Joe Pye weed and pale indian plantain are in full bloom down by Meetinghouse Creek.
While I drew, fall field crickets trilled in the field behind me, and a white-breasted nuthatch’s loud and nasal ank ank! ank ank! ank ank! gave away his position as he walked head-first down the trunk of an oak looking for insects. I remember the bird’s name and differentiate him from the brown creeper, who also hops on tree trunks, by thinking what a “nut” the nuthatch is to hop head-first straight down the tree. The way a brown creeper does it, starting at the bottom of the tree and spiraling up the trunk, seems so much easier. The name nuthatch actually comes from the bird’s habit of wedging nuts into cracks in a tree bark, then whacking at it with his sharp bill to “hatch” the nut from its shell.
A pileated woodpecker screamed several times close by. A breeze kicked up and stirred the leaves, eventually becoming a steadying cooling wind that persuaded me to stay a while after journaling, just to enjoy it.
We then walked through the shade garden to the road, down the road to the power line and then to the river. Today's theme was "vines," but we saw many other interesting things, both flora and fauna.
|Land Planarian (Bipalium kewense) on human finger|
Our first find (on the sidewalk in the shade garden) was a real surprise -- a land planarian (Bipalium kewense) that was attacking an earthworm.
Planarians are a type of free-living flatworm (Phylum Platyhelminthes). Flatworms are weird by human standards. They have no circulatory system and a single opening into the digestive tract (a mouth but no separate anus). The mouth isn't located on the head, but instead somewhere in the middle of the body, and also serves as the anus. The majority of flatworms are parasitic and cause many severe human diseases, such as schistosomiasis. (Tapeworms and liver flukes are other examples of flatworm parasites that afflict humans.) But the free-living flatworms are not parasitic and the land planarian we saw this morning is actually a predator, feeding on earthworms and other soil-dwelling animals. In fact we first thought we were seeing a "sick" earthworm. It's long, skinny tail turned out to be the land planarian attached to the posterior end of the worm. This species has no common name (Bipalium kewense) and was first discovered in Kew Gardens in England. It seems to have originated in SE Asia and has spread worldwide, probably via the horticultural trade.
The first vine we found ascending the arbor at the edge of the road. Identification was difficult because we couldn't see the leaves clearly, but the consensus was for Wisteria frutescens, our native Wisteria. (The Wisteria that grows on the arbor next to the parking lot is not a native, it is Chinese Wisteria and has to be frequently pruned to prevent it from escaping into the adjacent trees.
Vines have several methods of climbing up, on and over nearby plants. They can simply grow over other plants; they can get support by twining around the other plant stems; or they can use specialized structures like aerial roots or tendrils to hang on to other plants
|Aerial root of Poison Ivy|
The native wisteria growing on the arbor at the road edge is a nice example of twining. There are two plants growing up it, one is right-handed and the other left-handed. It seems odd to be talking about handedness in an organism that lacks hands, but a vine can twine in two directions. As it grows up a support it can encircle it to the right or left. Around the world about 90% of vine species are right-handed. A few are ambidextrous and the rest are lefties. The interesting question is why? Does it matter which way a vine curls around its support? There doesn't seem to be any obvious reason, but then why are most humans right handed?
The next vine we encountered, Poison Ivy (Toxicodendron radicans), is a wonderful example of a vine that climbs by means of aerial rootlets.
|Ilicium parviflorum fruit|
As we walked down the road we noted the star shaped fruits and licorice odor of the Yellow Anisetree (Ilicium parviflorum) and the enormous, bipinnate leaves of Hercules' Club (Aralia spinosa).
|Fruits of Virgin's Bower|
Near the wooden fence by the road we found Virgin's Bower (Clematis virginiana) that had finished blooming but the fruits were present, although they looked a bit bedraggled after yesterdays rain. This is a native species. We have previously seen Yam-leaf Clematis (C. terniflora) in the garden, an invasive look-alike. Virgin's Bower usually has 3 ovate, toothed leaflets whereas the other species usually has 5 untoothed leaflets.
This is the season when orb weaving spiders become obvious. Their webs always seem to be about face high and strung across the trails in the garden. It's always annoying to walk into one, but did you ever stop to wonder how a little spider got that elaborate web stretched from side to side in a trail?
A web begins with the construction of a framework. This silk is not sticky and its function is to provide a scaffolding on which the sticky capture threads can be hung. The framework begins with a spider climbing to suitable height, elevating its abdomen and releasing a strand of silk with a sticky end. Silk is very light and can be carried away by the gentlest of breezes. Eventually the free end is caught in nearby vegetation and the spider pulls it taut. The spider then anchors her end of this strand and attaches another strand of silk to its resting place and proceeds to walk across the first line, producing a second silk strand as she goes. When she gets to the end of the first strand she anchors the second silk line and then walks back to the center of the second line. Then she attaches a third line to the middle of the second line and drops to the ground, spinning out the third line as she descends. Upon reaching the ground she reels in the third line, which pulls down on the center of the second line and creates a triangular frame which is the beginning of the framework for the capture web.
We saw three different orb weaver spiders today.
|Yellow Garden Spider|
Yellow Garden Spider (Argiope aurantia) with a nearby egg case.
|Yellow Garden Spider egg case|
Spinyback Orbweaver (Gasteracantha cancriformis). This spider spins a web with the characteristic thread pattern: thin, fuzzy, thin, . . .
Spined Micrathena (Micrathena gracilis)
One of the very tall grasses that attracted our attention was Silver Plume Grass (Erianthus alopecuroides). We saw several scattered specimens, each around 9 feet tall.
In the damp areas of the power line we saw dense stands of two kinds of Smartweeds (family Polygonaceae): Waterpepper (Persicaria hydropiper) with tiny white flowers and a Smartweed (Polygonum sp.) with tiny pink flowers. Neither of these plants is on our list for the garden so you might want to add them. Several clumps of Rushes were also seen growing with the smartweeds. These are difficult to identify so I'm not going to attempt to give a name to them. You can distinguish among rushes, sedges and grasses by using the following ditty:
Sedges have edges.
Rushes are round.
Grasses have joints,
All the way to the ground.
We found the unusual parasitic plant, Dodder (Cuscuta sp.), and it was flowering! Only a short segment of its orange stem was visible. Dodder twines around the host plant and sinks root-like structures, called haustoria, into the vascular system of its host. It's the vampire of the plant world. I have never seen Dodder in the Botanical Garden before and it is not on the plant list -- another one we need to add.
|Small White Morning-glory|
Also in bloom was Small White Morning-glory (Ipomea lacunosa), another plant that is missing from our list. Look carefully at Dan's photo of this plant and you can determine the direction of its twining.
Other vines growing in or near the power line right of way:
|Bur Cucumber flower|
Green Briars (Smilax sp.): several species are found in the garden natural areas; today we saw S. smallii. Most Smilax species use tendrils for support. Each leaf has two tendrils that arise from the petiole near its attachment to the main stem. When the tendrils come in contact with a support they coil around it and ultimately harden. If you have ever tried to remove a Green briar from another plant you know how tenacious their grip can be.
Camphorweed (Heterotheca latifolia)
Goldenrod (Solidago sp.)
Yellow Crownbeard (Verbesina occidentalis)
Ironweed (Vernonia gigantea)
|Tiger Moth caterpillar|
On the way back we discovered a slug crossing the road and stopped to examine it. Slugs are basically snails without shells, but they still retain a vestige of the mantle, the organ that, in snails, secretes the shell.
Then we retired as usual for conversation and snacks at Donderos'.