Friday, July 11, 2014

Wildflowers of 2014 - #172 through #181

After a lull in June, the pace of wildflower first blooms has picked up again.  Over the past two days I have added another ten species to the list - bringing the 2014 list to one hundred eighty-one species!

The first three species listed below were found Tuesday 08 July 2014 at Island Park.  Island Park is the most used (and most developed) park in Mt. Pleasant, but because it is completely surrounded by the Chippewa River it is a good place to find riparian species.

Wildflowers of 2014 - #172 Blue Vervain (Verbena hastata)

The first species of the day was Blue Vervain (Verbena hastata).  Also known as Swamp Vervain, Blue Vervain is water-loving species that is most commonly found in wet meadows, along shorelines, and in wetlands.  Blue Vervain has dark violet-blue flowers arranged on narrow spikes.  Individual plants may reach heights of 2 to 6 feet.

Blue Vervain (Verbena hastata)

Blue Vervain - a closer view of the flower spikes

For more information on Blue Vervain, please see this species profile from July 2013.

Wildflowers of 2014 - #173 Purple Loosestrife (Lythrum salicaria)

The second flower of the day is one that I hope not to find every year, but I know that I will.  Purple Loosestrife (Lythrum salicaria) is a native of Eurasia, northwest Africa, and Australia.  It was introduced in North America originally as an ornamental plant in the 1800s.  Unfortunately, this plant easily escapes cultivation - individual plants may produce more than 2 million seeds in a single year!  Once established in a natural area, it becomes almost impossible to eradicate and quickly outgrows the native vegetation.  It can now be found in 43 states and 10 Canadian provinces and territories.  Many wetlands that have been infested with this plant have become almost complete monocultures, with little to no native vegetation remaining.

Purple Loosestrife growing along the Chippewa River

Purple Loosestrife is fairly easy to identify.  Its flowers are arranged in spikes at the top of the plant.  Individual flowers are purple, have 5-7 petals (normally 6), and measure 1/2 to 1 inch across.  Flowering spikes may be 6 inches to 2 feet long.

Purple Loosestrife - a closer view of the flowering spikes

Purple Loosestrife leaves are lanceolate (shaped like a lance or spear point) and may measure up to 4 inches long.  They are normally arranged in opposite pairs or whorls of three leaves, although some upper leaves may be arranged alternately.  Plants may grow to 6 feet in height, but may flower when less than 12 inches tall.  Another distinguishing feature of Purple Loosestrife in the square cross-section of the plant's stem.

Purple Loosestrife - note the opposite leaves and square stems

Wildflowers of 2014 - #174 Wild Mint (Mentha canadensis)

The next plant also has stems with a square cross-section, but this plant is native to North America.  Wild Mint (Mentha canadensis) is the only native mint that can be found in Michigan.  It grows in moist soils in a variety of habitats, both sun and shade.  It has a circumpolar distribution - meaning it occurs as a native plant in North America, Europe, and Asia.  European and Asian plants are referred to as Mentha arvensis - the USDA PLANTS database also lists North American plants by this nomenclature.

Wild Mint (Mentha canadensis)

Like other mint species, Wild Mint has a distinctive "mint" smell and taste which may deter browsing by herbivores.  Wild mint can be distinguished from the other mint species found in Mid-Michigan by the location of its flowers.  All of the non-native Mentha varieties have flowers arranged in spikes; Wild Mint has white (or pink or lavender) tube-shaped flowers arranged in whorls growing from the leaf axils on the upper part of the plant.

Wild Mint - note flowers in leaf axils and hairy stems

The following seven species were photographed at Mill Pond Park on Wednesday 09 July 2014.

Wildflowers of 2014 - #175 White Vervain (Verbena urticifolia)

The first flower from Wednesday was White Vervain (Verbena urticifolia).  This plant is very similar to #172 Blue Vervain (V. hastata) - the plants are so closely related that they may hybridize.  The major difference between the two species is flower color.  While those of Blue Vervain are a deep violet blue, White Vervain flowers are (of course) white.  The flowers are arrange on clusters of spikes like those of Blue Vervain, but the spikes of White Vervain are less compact and tend to sprawl more.  Leaves of White Vervain also tend to be wider than those of Blue Vervain.  The leaves resemble those of Nettles (Urticaceae), thus the urticifolia in the species scientific name.

White Vervain - note nettle-like leaves

White Vervain - note small white flowers and opposite leaves

White Vervain is found in moist soils.  It is more tolerant of partial shade than Blue Vervain.  It is often found in open woodlands and wooded floodplains where Blue Vervain is not present.  It has a smaller natural range than Blue Vervain.  While Blue Vervain is found from the Atlantic to the Pacific Coast, White Vervain is only found east of the Rocky Mountains.

Wildflowers of 2014 - #176 Stinging Nettle (Urtica dioica)

The previous flower provides a nice segue into this next species; White Vervain's binomial nomenclature Verbena urticifolia means Verbena "with nettle-like leaves".   The next flower on the list is a nettle - Stinging Nettle (Urtica dioica).

Earlier this week I listed Wood Nettle (Laportea canadensis) at #164.  Although Wood Nettle and Stinging Nettle are in separate genera (Urtica and Laportea), they share a common characteristic.  Both plants are covered with fine needle-like hairs that break off upon contact.  These needles are filled with filled with a mixture of chemical that cause an itching or burning sensation upon contact with skin.  Both plants also have small greenish-white or green flowers growing in clusters from the leaf axils.

Stinging Nettle - note opposite leaves and flowers in leaf axils

Despite these similarities the two plants are easy to distinguish.  Stinging Nettle often grows taller than Wood Nettle (up to 7 feet tall versus 4 feet tall).  Although both species like wet soils, Stinging Nettle is also more likely to be found in dry habitats than Wood Nettle.  The most distinguishing characteristic is leaf placement; Wood Nettle has some alternate leaves while those of Stinging Nettle are always arranged in pairs.

Stinging Nettle - a closer view of the greenish-white flowers

There is some debate over the origin of our Stinging Nettle plants.  The species is native to both North America and Eurasia.  Michigan Flora indicates that most Michigan plants belong to the native subspecies.

Wildflowers of 2014 - #177 Bouncing Bet (Saponaria officinalis)

The next three species are all non-native, starting with Bouncing Bet (Saponaria officinalis).  This native of Eurasia is naturalized across all of the United States and Canada with the exception of Hawaii, Alaska, and the Canadian Arctic.  Like many introduced species, it is most commonly found in disturbed habitats such as fields and roadsides.  Bouncing Bet is also known as Soapwort - adding the plant to water will result in foam that has traditionally bean used for cleaning.

Bouncing Bet or Soapwort

Bouncing Bet plants may grow up to 2 1/2 feet tall and produces a terminal cluster of white or bluish-white flowers.  The flowers are up to 1 inch across, tube-shaped, and have five petals.  The petals angle backward, exposing the plant's pistil and stamen.  Like many pale flowers, Bouncing Bet is probably pollinated mainly by large nocturnal moths.

Bouncing Bet - note tubular flowers with bent back petals

Wildflowers of 2014 - #178 Bull Thistle (Cirsium vulgare)

Bull Thistle (Cirsium vulgare) is the second species of thistle on the list - Canada Thistle (C. arvense) was listed at #150 on June 22nd.  Like Canada Thistle, Bull Thistle was originally native to Europe.  It has naturalized across most of North America (except certain areas of the Canadian Arctic).  It was probably introduced accidentally in seed stocks.

Bull Thistle - note spines on stem, leaves, and flower bract

Bull Thistle is a very spiny plant.  The stem of the plant is covered with small spines and several linear "wings" with widely spaced large spines.  The leaves of the plant are lobed, with stout spines at the tips of each lobe.  The bracts at the base of each  purple/pink flower also come to stiff points.

Bull Thistle plants grow to a height of 3 to 6 feet.  They are most commonly found in dry upland sites.

Wildflowers of 2014 - #179 Catnip (Nepeta cataria)

Catnip (Nepeta cataria) is another Eurasian native that has also naturalized across most of North America.  Also known as Catmint,  Catnip was widely planted during Colonial times for its medicinal properties.  Like most non-native species, it is most common in disturbed habitats.

Catnip grows to a height of 1 to 3 feet.  It has opposite leaves that are roughly heart-shaped with toothed margins.  The undersides of the leaves and stems are covered with dense whitish hairs - this gives the plant a grayish-green appearance.

Catnip (Nepeta cataria)

Catnip Flowers are arranged in a spike at the top of the plant and in the upper leaf axils.  The flowering spike may be nearly 3 inches long, but individual flowers are small (1/4 to 1/2 inch across)  The flowers are white with pink or purple spots.

Catnip - note white flowers with pink/purple spots

Wildflowers of 2014 - #180 Swamp Milkweed (Asclepias incarnata)

Species #180 for the year is Swamp Milkweed (Asclepias incarnata).  This is the second Milkweed species on my 2014 list - Common Milkweed (A. syriaca) was listed at #156.  In Mid-Michigan, Common Milkweed is our most widespread Milkweed species, Swamp Milkweed is the second most common species.  As its name implies, Swamp Milkweed prefers wet soils.  Although the plant is not usually found in standing water, it is common along shorelines, in wet meadows, and in ditches across Michigan.  It rarely is found in drier soils.

Swamp Milkweed (Asclepia incarnata)

Swamp Milkweed is easy to identify.  It has flowers with the typical milkweed shape, but they are arranged in a flat-topped (or domed) cluster.  More importantly for identification they are a bright magenta pink.  The leaves of Swamp Milkweed are much narrower and lance-shaped than those of Common Milkweed.  The plant has the potential to grow up to six feet tall, but is usually much shorter.  Like all Milkweeds, Swamp Milkweed is a perennial that spreads both by sending up clones from its roots and by its wind-dispersed seeds.

Swamp Milkweed - note narrow lanceolate leaves and magenta flowers

Wildflowers of 2014 - #181 Pickerelweed (Pontederia cordata)

The final flower of the day was Pickerelweed (Pontederia cordata).  This plant grows in shallow water along shorelines, in ditches, and in emergent marshes throughout the eastern United States and Canada (plus a disjunct population in Oregon). 

In Mt. Pleasant, I can find Pickerelweed in a single location, a ditch coming off of a small wildlife.  This ditch is rapidly being filled in with Narrow-leafed Cattail and I imagine that in a few years, the Pickerelweed will probably be crowded out.

Pickerelweed - note violet blue flowers and heart-shaped leaves

Pickerelweed plants can grow to a height of more than three feet.  Their basal leaves are roughly heart-shaped and measure up to 7 inches long.  The small violet-blue flowers are about 1/4 inch across and grow on a crowded spike (raceme) that may be 2 1/2 inches long.  These flowers attract bees, butterflies, and day-flying moths.

Pickerelweed - a closer view of the flowering spike

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