Thursday, July 18, 2013

Canada Thistle

Beware of tall, attractive wildflowers with prickly leaves growing in fields. Most have beautiful magenta or lavender-colored heads, but the leaves, and sometimes the stems, are edged with numerous, sharp spines to defend against herbivores looking for an easy meal. These are the thistles. They are composites, related to daisies and goldenrods in spite of the obvious differences. Most are biennials, starting as a ground-hugging rosette of prickly leaves the first year, then growing tall and flowering the second.

The Canada Thistle (Cirsium arvense), a misnamed alien invasive from Europe, is one of the less-obvious species here [in the northern Finger Lakes region of NY] because its light-purple heads are less than an inch high. The whole plant grows four to five-plus feet high and often forms dense colonies after spreading by underground stems. In Europe and northern Asia, it is known as Creeping Thistle. One plant's roots can spread to a three-foot diameter (or more) in one year and continue growing at this rate for many years, making it a difficult plant to eradicate. A single thistle plant can be considered biennial, but the root system is perennial and continues to put its energy into new clonal [cloned] shoots.
Canada Thistles form colonies from a spreading underground
 root system. Less energy goes into producing flowers.
Less energy goes into producing flowers which are usually dioecious (either male or female). Male flowers may be slightly smaller, but otherwise similar. Both are very fragrant, which is energy spent to attract pollinators and NOT humans. Female flowers produce 40 to 80 seeds per head, but the fuzzy pappus is loosely attached and often ineffective in seed dispersal.

Canada Thistle's main stems are smooth, but the deeply-lobed leaves are designed to keep you at a distance. In the spring, wear heavy gloves and protective clothing so you can return to the location and collect the young leaves, young stems and roots for food. One of the plant's nicknames is "lettuce from hell" (and it actually is related to lettuce). After removing the spines, add young leaves to salads or eat them cooked. The pithy, young stems are easier to deal with; just peel and eat raw or cooked. The roots of first year plants, before the tall stems begin, are a survival food, but they also can cause flatulence.

A crab spider is camouflaged against a Canada Thistle flower bud.

Canada Thistle is also food for wildlife, especially goldfinches and other finches that eat the seeds. Some butterfly and moth larvae eat the leaves. Look for Red Admirals, Viceroys and Painted Ladies on this thistle. The larvae of the Orellia ruficauda fruit fly parasitize the fertile seed heads, making them a somewhat-effective biological control.

In the past, a tea made from the leaves was used as a general tonic (stimulant) and diuretic to increase the loss of water from the body. Externally, it was used for skin sores and poison-ivy rash. Native Americans used a root tea as a digestive tract stimulant and dewormer. (I wonder what they used before Europeans introduced this wildflower.) At the other extreme, it was said to cause inflammation and irritation (Jacobs and Burlage). Go figure.

Cirsium comes from the Greek word, kirsion, from kirsos, a "swollen vein" remedied by one of the species in that genus. The species name, arvense, is Latin for "in the field." Among its other common names are "field thistle," "perennial thistle" and "cursed thistle." It was originally native to the Mediterranean and southeast Europe and likely arrived in North America during the 1600's.

Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.

Wednesday, July 10, 2013

Ash-tree Bolete

Ground-level view of an Ash-tree Bolete cluster on a grassy trail

Mushroom species are seasonal in nature, much like wildflower species, but unlike plants, they do not require sunlight. For most of the year, they are underground or growing inside dead wood or otherwise out of sight. Rain is good for mushrooms and this year holds promise of an abundance in the Northeast, both in number of species and a surplus of each type. When mushrooms "suddenly" appear, what we see are just the fruiting bodies with the sole function of releasing spores (think evolutionary predecessors to seeds). They will drift on the wind and those that find suitable landing pads will develop into new, hidden networks underground or inside rotting logs, and these may last for years.

Top and bottom of Ash-tree Bolete caps.

While the familiar mushrooms have radiating gills that produce the spores on the undersurface of the caps, Boletes are a family of mushrooms (Boletaceae) that have a spongy layer of pores or tubes on the underside to do the same job. Boletes are soft, fleshy and stalked and often grow in the woods. Many of the 200 North American species are edible, but only a few are worth the effort of collecting, and several are poisonous, so beware.

Angular pores radiating away from the stalk at the edge of a cap.

Where do you think Ash-tree Bolete (Boletinellus merulioides) grows? (one guess) Well, true to its name, in our yard it grows on the grassy and moss-covered trails under the ash trees. Numerous brown caps, averaging three to four inches across, are growing either singly or in tight clusters. The older ones are wavy-edged and distorted. On the yellow underside of each cap, a network of irregular ridges and cross-ribs creates a fine pattern of angular, shallow pores giving this mushroom the nickname, "shallow-pore." The thin folds can appear almost gill-like as they radiate away from the off-center stalk. (Sometimes the stalk is lateral, or attached at the edge of the cap.) If bruised, the pores turn blue-green, then reddish-brown. Beware, some of the toxic Boletes are blue-staining.

A row of Ash-tree Boletes on a grassy trail under a grove of ash trees.

Ash-tree Bolete (also called Boletinus porosus and Gyrodon merulioides in some field guides) grows from Michigan to Eastern Canada and south to Texas and Florida. This species is edible, but not recommended, partly because of the chance of confusion with several toxic boletes. That risk aside, the quality and flavor are said to be poor, at least in comparison to better mushrooms.

It's likely a snail scraped part of the right cap to make a meal.
The left cap is turned over to show the underside pores.
Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.

Sunday, July 7, 2013

Black Raspberries


I have mixed feelings about early July. On the down side are the humidity and the mosquitos (which seem to have reached a new peak). On the positive side, the wild Black Raspberries are ripe. For years, I've been encouraging these bushes to grow around the perimeter of our property. Even though they're thorny and often hook me on the arm or in the hair, the rewards seem to be worth it.

Black Raspberries are native to eastern North America.

The common species is Rubus occidentalis, but similar varieties are numerous. They belong to the rose family, making them direct relatives of blackberries, strawberries, rose hips, cherries, plums, apples and pears. They are nicknamed "black caps" or "thimbleberries," referring to the way the ripe fruit separates easily from the pedicel leaving a round button called a carpel or receptacle (which seems misleading). True blackberries, a distinctly-different species, do not separate from the receptacle. Individual raspberry fruits are composite clusters of small beads called drupelets, each containing a tiny seed. The dark-purple color is produced by anthocyanin pigments which makes them useful as natural dyes -- witness the color of your fingers after picking a few. Raspberries are also healthy. The anthocyanins are powerful antioxidants and are being tested for their effect on cancer.
Raspberry canes have a whitish, powdery bloom, best seen at upper left
It takes raspberry canes a year and a half to mature and bear fruit. The first year, the canes (green with a whitish, powdery coating) bear compound leaves usually with three leaflets but sometimes five arranged palmately (like fingers or spokes from a single point). The undersides of the toothed leaflets are silvery white, much like Silver Maple leaves. The second year, the canes turn dark purple or reddish, but the remaining powder makes them look bluish. They send out short branches that produce alternate, compound leaves with only three leaflets (unfortunately resembling poison ivy). Flowers with five white petals appear in May and these develop into red fruits which turn dark as they ripen around July 4th, give or take, here in the Finger Lakes region of New York. After the fruit is gone, you can still use the leaves to make tea.

The undersides of Black Raspberry leaves [turned over at right] are nearly white.

The arching canes may root at the tip if they touch the ground. In this way, one shrub can form broad colonies that provide protective cover for small mammals. During the winter, the canes of all brambles (including dewberries, black and red raspberries and true blackberries) become food for cottontail rabbits. Canes die at the end of their second year, but the roots continue to send up new shoots every spring.

Black Raspberries are native from Wyoming to Ontario and Quebec and south to Georgia and Mississippi. If you live in this area and want to collect raspberries, you need to get to them before the songbirds, game birds and wild mammals of all sizes. If you want to grow your own, they tolerate a wide variety of conditions from open sunlight to shade and soils that are moist or dry. They will grow in open woods, thickets, stream banks, wet meadows and old fields as well as the edge of your lawn. If you leave a spot around some trees unmowed, the birds will probably drop some seeds and help you get started. In two years you'll be on your way to healthy eating.

Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.