Why do some Trees Lose their Leaves for the Winter?

Posted on November 20, 2018 by admin

Sugar Maple leaves

In Michigan our broadleaved trees shed their leaves every autumn and most of our conifers hold their leaves (needles) for multiple years. All of our broadleaved trees are true flowering plants also known as angiosperms. Our conifers are non-flowering plants called gymnosperms. They have pollen cones and seed cones that technically are not flowers.

Tamarack trees before needle drop

Tamarack is our only native conifer that drops its needles for the winter. Our other conifers do not hold their needles forever but shed some each year, normally in autumn. White and Jack Pines hold needles for two years, Red Pines four to five years, White and Black Spruces, and Balsam Fir seven to ten years. Evergreens photosynthesize year round. Their needles have a waxy coating called the cuticle which slows down water loss. Evergreens are also less tasty to predators than broadleaved trees. Evergreens tend to have an upright growth making them less likely to get damaged by accumulating snow.

White Pine showing third year needles about to fall

Deciduous trees shed their leaves at the end of the growing season. This prevents water loss through the large surface area of the leaves. Deciduous trees catch little snow in the winter. In southern Michigan we had an early snow before the leaves dropped and many limbs were broken from the weight of the snow. Leaves on deciduous trees are often damaged during the growing season by insects, fungi, animals, or wind. This annual replacement refurbishes the leaves. Some writers suggest that the bare branches at flowering time allow for better pollination especially for wind-pollinated species.

When deciduous trees start losing their leaves they reabsorb some of the nutrients from their leaves. Chlorophyll, the green color in the leaves, is one of the first chemicals to be broken down and absorbed. This is why tree leaves turn colors in the fall. In Michigan each group of trees normally has a distinct color. Ashes tend to be red-purple, Oaks yellow-brown, Aspens yellow, Sugar Maples orange-red, Silver Maples yellow, Red Maples red, Sassafras orange, and Hickories yellow. Color varies from season to season and exceptions to these general rules are common. However, with a little practice it is possible to locate particular tree species by their color.

Thanks to my friend Judith who suggested this blog post.

References

Conners, Deanna. (November 2017) Earthsky. https://earthsky.org/earth/why-do-trees-shed-their-leaves

Strieby, Sandra. (July 2013). Washington Native Plant Society Blog. https://www.wnps.org/blog/conifers-deciduous-trees

Panich, Justin. (No Date). Bioweb. http://bioweb.uwlax.edu/bio203/2010/panich_just/Site/Adaptations.html

Barnes, Burton V. and Warren H. Wagner Jr. (2004). Michigan Trees: A Guide to the Trees of the Great Lakes Region, Revised, Updated Edition

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Running Ground-pine in Michigan

Posted on September 18, 2018 by admin

Lycopodium clavatum – Running Ground Pine

Michigan has two species in the genus Lycopodium: L. clavatum and L. lagopus. They are both called Running Ground-pine. L. clavatum is also called: Common Clubmoss, Stag’s-horn Clubmoss, Wolf’s-foot Clubmoss, and simply Ground Pine. L. lagopus is called: One-cone Clubmoss, Ptarmigan Clubmoss, and Arctic Stag’s-horn Clubmoss. Additional common names are also in print. I tend to call them Clavatum or Lagopus and leave it at that.

Lycopodium lagopus – Running Ground Pine

The remaining Michigan Clubmoss species that once were in Lycopodium are now found in five other genera. If you desire more information on these Clubmosses then consult Dan Palmer’s new book Michigan Ferns and Lycophytes: A Guide to Species of the Great Lakes Region.

The two species of Running Ground-pine are easily distinguished when seen in the field, but sometimes herbarium specimens are difficult to determine. Clubmosses have sun forms and shade forms. Sun forms are normally more compact than shade forms. In the field you know if you have a sun or shade form but it often is not obvious with a pressed specimen.

L – Lycopodium clavatum R – Lycopodium lagopus

Clavatum has multiple strobili (cones) that are semi-alternate on the pedicel. A rare pedicel will have one strobilus, so check a large part of a colony to determine the number. Its leaves are awn tipped meaning they taper to a hair-like tip. They are ascending, at least in the shade form. Leaves on shade form Clavatum are slightly longer and spread more than the appressed leaves on Lagopus. Lagopus has leaves 3 to 5mm long and Clavatum has leaves 4 to 6mm long. Sun forms of Clavatum have leaves that resemble shade form Lagopus. Clavatum is seen more in Michigan than Lagopus.

Lycopodium clavatum sun form top L. lagopus shade form bottom

Lycopodium clavatum shade form top Sun form bottom

Lagopus normally has a single strobilus. A rare pedicel will have two strobili but they will be sessile (stalkless). This might result from damage to a developing strobilus. Its leaves are also awn tipped but tend to be more appressed than Clavatum. Lagopus branches are more upright than Clavatum.

It would be nice to have a few more characteristics to use to separate these two species. An amateur botanist should find and study a colony looking for other differences. Once we understand more about each species’ variations then we might find other consistent ways to tell them apart.

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A Cockroach, a Beetle, and a Fly

Posted on August 20, 2018 by admin

Wood Cockroach on Cup-plant

Yesterday, I made a quick stop at the Royal Oak Arboretum to check on the progress of our Canada Thistle control. I took my camera along. I spotted a Wood Cockroach (Parcoblatta sp.) feeding on the wilting flowers of a Cup-plant (Silphium perfoliatum). I took a few quick photos.

Cup-plant

Wood Cockroaches are in the same family as the German Cockroach (Blattella germanica). German Cockroaches are the night marauding, indoor living pests. Wood Cockroaches are day active and seldom seen indoors. If they get into a house, they cannot survive in the environment and as a result are short-lived. They feed on decaying organic matter.

Shining Flower Beetles

When I viewed my images on a computer monitor, I could see that the black specks I thought were abnormal flowers on the flower disk were tiny black beetles. These were Shining Flower Beetles (Olibrus sp.). Approximately 30 species of this genus occur in the United States and they require a modern treatment so we can better understand them. Adult Shining Flower Beetles feed on the flower-heads of the Aster Family (Asteraceae). Larva develop in the flower-heads of the Aster Family. Each Shining Flower Beetle species appears to use a specific plant species.

I made another quick trip to the arboretum and as I was photographing the tiny beetle an interesting fly of an unknown species came onto the flower.

Fly on Cup-plant, probably a fruit fly in the genus Drosophila

Standing next to this plant for less than five minutes; I wondered what I would have seen if I had hours to study this small area. Get outdoors, find a patch of flowers, stand there, and look for insects. I can’t identify every insect I see but they still fascinate me.

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How to Identify Wildflowers

Posted on July 11, 2018 by admin

Goat’s-Rue

On the Fourth of July I visited Indian Springs Metro Park. I found a plant in flower that I didn’t know. It was obviously in the pea family so I looked at the Michigan flora website and the dichotomous key to the pea family (Fabaceae). A dichotomous key is simply a series of paired statements: you read both statements and follow the statement that matches your plant.

Pea type flowers -L Once-pinnately compound with odd number of leaflets – R

Starting with couplet #1 I follow the lead for a plant with compound leaves, that takes me to couplet 3. My unknown plant has twenty-one leaflets, that leads to couplet 27. My plant is an herb not a woody plant, that leads to couplet 33. Its leaves are once-pinnately compound so we follow couplet 36. Our unknown has an odd number of leaflets so we follow couplet 44. Our leaflets are wider than 3mm that takes us to couplet 45. Inflorescence a simple spike or raceme leads to couplet 48. Its stem is not vine-like couplet 49. The flowers are bicolor so the key leads us to the genus Tephrosia. This genus, in Michigan, has only a single species Goat’s Rue or Rabbit-pea (Tephrosia virginiana). I check the images on the site and they match my plant.

It takes some practice to master a botanical key. You need to learn a vocabulary. Words such as: leaflet, raceme, inflorescence are all descriptive of plant parts. I still look up words in the glossary or a dictionary from time to time. The keys on the Michigan Flora website are excellent and work well. There is also a key to families.

Richard Rabler’s Plants of Michigan has simple keys and can be used as a stepping stone to more technical works. It has few illustrations but covers a large number of species, including grasses, sedges, and woody plants. When I started learning to use a key I would identify plants that I already knew just to get a feel for how the key worked.

Irregular Flowers and simple spike – L Alternate Leaves – R

Newcomb’s Wildflower Guide is a great beginner’s guide. Inside the front cover is the start of a simple key. You look at three aspects of the plant: flower type, plant type, and leaf type. A three digit number is created from this information. I use Newcomb’s if I don’t know which family the unknown belongs to. Our plant has irregular flowers, alternate leaves, and divided leaves. This gives us the group number 134. In the locator key under group 134 is a series of statements. Our plant has more than four leaflets that leads us to page 66. From the description and drawings on page 66 we reach Goat’s Rue. Newcomb’s key is simple, it has drawings of flower and leaf type and a glossary. Most of the species are illustrated with line drawings. It has fewer species than Michigan Flora or Plants of Michigan but includes most of Michigan’s showier species. The scientific names are old but a PDF document updates them.

Field guides arranged by flower color are not the best method to identify plants. Using Goat’s Rue as an example the flower is both yellow and pink. Some plants change flower color as they age. Albino and other color forms also occur.

Plant photos can be posted on the Michigan Botanical Society Facebook page and someone usually identifies them. Post where and when the photo was taken.

I encourage you to try to identify your own unknowns. I find that I remember a species better if I made the effort to identify it.

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Beach-Heath

Posted on June 25, 2018 by admin

Beach-Heath

I found Beach-Heath, also called False Heather (Hudsonia tomentosa) in Crawford County, Michigan. Its typical Michigan habitat is the sand dunes along the Great Lakes. I found it in the middle of the Lower Peninsula. I know of several records from Crawford and Kalkaska Counties but in my almost four-decades of botanizing in these counties I had not found it before. It was growing in raw sand and some of my photos look like a Great Lakes sand dune. Vegetation was moving into the area: reindeer lichen (Cladonia sp.), and grass. This bank was cut down when the road was moved and paved approximately fifty-years ago.

Beach-Heath L Mossy Stonecrop R

From a distance it resembles Mossy Stonecrop (Sedum acre) which also can grow in raw sand. Up close the narrow, tiny, blue-gray leaves covered with white hairs and bright yellow, five-parted flowers left no doubt that it was Beach-heath. The clumps of plants appeared to flower starting from the outside and then moving to the center. While I could detect no fragrance from the flowers numerous mining bees were busily pollinating.

Beach-Heath flowers L Mining Bee R

I wonder how many other unreported inland colonies exist. If you don’t see the plant during its limited flowering time it might go unnoticed.

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A New Michigan Fern Book

Posted on June 17, 2018 by admin

With the publication of Michigan Ferns & Lycophytes: A guide to species of the Great Lakes region by Daniel D. Palmer, Michigan gains a long needed handbook. The University of Michigan Press should be proud to produce a fern book modeled on Michigan Trees by Barnes and Wagner and Michigan Shrubs and Vines by Barnes, Dick, and Gunn. Palmer’s book is a worthy addition to this high standard.

The illustrations are scanned images of fern specimens, mostly from fresh material. They are superb, showing key characters such as horsetail stem cross-sections, pinnule and sori enlargements and stipe cross-sections. The keys are excellent. I ran ten different species from my garden through the keys and they worked flawlessly. I then tried a woodfern hybrid and it, of course, did not work below the genus level but with the help of the Dryopteris summary chart I could tell it was Dryopteris xmontgomeryi. Even difficult genera such as Cystopteris (Brittle Ferns) and Equisetum (Horsetails and Scouring-rush) worked well. Not all hybrids are treated in depth except the two common Woodfern hybrids (Triploid Woodfern and Boott’s Hybrid Woodfern) and the four common Horsetail hybrids. The Horsetails have two keys: one termed only a “key” and a second one labeled an “Informal Key to the Michigan species of Equisetum in Midsummer.” Both look quite useful. Summary charts are provided for difficult genera or species pairs. Also helpful are hints on how to distinguish a species from a similar one.

This book is more than a mere identification handbook. It is loaded with helpful tidbits of scientific facts. What the meaning of the scientific name is. The origin of the common name. Reasons behind a revision in the scientific name. Palmer explains Lycopodium powder and the superstitions surrounding the Moonworts. We are told that Rough Scouring Rush is used to “prepare reeds for musical instruments.” Discussions of how hybrids become fertile, the life-cycles of true ferns and lycopods, Michigan fern ecology, nomenclature and synonymy are helpful. Botanical “jargon” is used and can intimidate a beginner. Here again the book helps the beginner. It has a fine written glossary, and an illustrated glossary on pages 67-71.

The maps are the most complete ever printed for Michigan. They are based on specimen records only and show the general range well. They also indicate where further collecting is needed to fill in the large gaps.

I found only a few minor errors. On page 37 Equisetum hyemale subsp. hyemale is contrasted with itself when subsp. affine is meant. On page 184 in the etymology of Osmunda regalis var. spectabilis it is stated that: “Asa Gray named the American variety spectabilis, ‘showy’.” Willdenow named it spectabilis, Gray transferred the name. My quibbles are minor.

Everyone interested in Great Lakes botany should own a copy of this book. With this book Palmer has placed in the reader’s hand all the information required to contribute to the further understanding of Michigan’s pteridophyte flora. The study of ferns and lycopods in Michigan has a long history of “amateurs” making significant contributions. This book will allow that tradition to continue.

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Sweet Gale: an often overlooked shrub

Posted on May 14, 2018 by admin

Sweet Gale leaves and staminate buds

Sweet Gale (Myrica gale) is one of our earliest flowering shrubs. It blooms in April or early May in northern Michigan along with the Willows (Salix spp.) and soft maples. Its leaf buds are small on brownish-red, shiny, stems. Staminate (male) flower buds are larger, cigar shaped, and at the branch tips. Staminate flowers form catkins 20-25mm [3/4-1 inch] long. Their triangular scales are covered with fragrant resinous dots. I think the catkins resemble small Viking horns. Pistillate (female) catkins are red to brown and their divided, threadlike, stigmas remind me of an artist’s brush. It flowers before the leaves appear. Plants are dioecious meaning pistillate and staminate flowers are on different shrubs. Wind pollinates this plant.

Sweet Gale staminate flowers

Sweet Gale pistillate flowers – L Upper surface of leaves showing glands – R

The leaves appear after the flowers in an alternate arrangement (one leaf at each node). They are simple, oblanceolate (wedge-shaped, broadest near the leaf tip) with a few fine teeth near the tip and very fragrant. If you brush your hand against the leaves it will pick up the fragrance. The upper and lower leaf surfaces are dotted with golden glands.

Sweet Gale leaves and seed heads

Sweet Gale is a low shrub, seldom taller than 1.5m [5 feet] growing in low areas or on banks of streams and ponds. It likes to have its roots inundated by water in the springtime. It is common in Michigan north of Saginaw. Get out and look for it while it is still blooming. Most people walk by this shrub without paying it any attention.

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Labrador-tea

Posted on April 4, 2018 by admin

Labrador-tea L – Flower Bud R – seed capsules

Labrador-tea (Rhododendron groenlandicum) is an evergreen shrub growing in sunny acidic locations. It prefers wet locations. I recently visited a location and observed it in its winter condition. Its evergreen leaves shrivel up to conserve moisture. They are revolute meaning the margins curl under the leaf blade. The young leaves have white woolly hairs that turn rusty–brown with age. A large terminal flower bud appeared on most branches with a small lateral leaf bud. Seed capsules were still present and will persist for several years. They are unique in the way they split, starting from the base and opening upward.

Labrador-tea leaves showing woolly hairs and curled leaf margins

One of my favorite sights in early summer is the white flowers of Labrador-tea along the edge of a bog. They bloom in terminal clusters, held high above the leaves. Insects pollinate them and often they are visited by solitary bees.

Labrador-tea in bloom

Labrador-tea is common in the Upper Peninsula and the Northern Lower Peninsula. It was known as Ledum groenlandicum. Because it easily hybridizes with other Rhododendrons in cultivation it should not be in its own genus.

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Boxelder Bugs

Posted on February 28, 2018 by admin

Eastern Boxelder Bug R-closeup showing ocelli eyes

Recently, I found an Eastern Boxelder Bug (Boisea trivittata) in my kitchen. I know the females often seek shelter in homes during the winter but I have never seen one here. They don’t lay eggs inside or destroy anything by eating it, but they can become a nuisance if hundreds or thousands of them invade a home. If this occurs their droppings can stain an area. I have found six of them so far, one at a time. I moved them to my garage.

They also have other common names: Maple Bug, Democrat Bug, Populist Bug, or Politician Bug. Boxelder (Acer negundo) is a true maple also known as Ash-leaved Maple; hence the first common name. Boxelder Bugs lay their eggs on the foliage and seeds of Boxelders and swarms of these insects are sometimes found during late June when the political conventions take place. Hence the latter names. The Eastern Boxelder Bug passes through five instars as it develops. They all look quite different from each other. Only the overwintering adult females invade houses.

Adult Eastern Boxelder Bugs are dull gray with red stripes along the wing edges and on the center of the pronotum. True bugs have a pronotum which is the segment behind their head.

The Eastern Boxelder Bug has two additional smaller eyes on the top of their head. These are ocelli eyes and they have only a single lens. They might only sense light areas and not images. It is difficult to determine their true function.

Adult Large Milkweed Bugs (Oncopeltus fasciatus) look similar to the Boxelder Bug. They have a black band across the middle of the wing, a black diamond toward the head and a black triangle on the tip of the wing. The remainder of the bug is orange or yellow-orange. It rarely invades houses.

Large Milkweed Bug

Another look alike is an adult Small Milkweed Bug (Lygaeus kalmii). It is black or gray with a reddish “x” that does not cross on the wings. It also rarely invades houses.

Small Milkweed Bug

Keep looking at Nature during the winter. You never know what you will find, even in your own home.

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Snowy Owl Quest

Posted on January 22, 2018 by admin

American Goldeneye L Phantom Snowy Owl R

I met Trapper Dave and Bobcat Bill at Foote Dam on the Au Sable River. Mallards and Common Goldeneyes swam below the dam. Cold air, -10 degrees F, and a five mile an hour breeze stung my cheeks. We headed toward the former Wurtsmith Air Force Base and possible Snowy Owls. We scanned the snow covered runways for owls. We saw no owls. Our only birds were a flock of Rock Pigeons on one of the hanger roofs. We decided to continue our owl quest at Tuttle Marsh.

Tuttle Marsh National Wildlife Area covers 5000 acres and is managed by the Huron National Forest. A loop road leads around the impoundment and my imagination turns every snow covered stub or small snow mound into an owl. We stop frequently and at one stop we find an otter slide. The otters crossed the road, slid down the bank and then pranced across a frozen pond. They are the only Michigan mammal to play solely to have fun.

We continue to the mouth of the Au Sable River and walk out the catwalk into Lake Huron. Shards of ice, several feet across, line the shore. Ice chunks float down the river and several Goldeneyes swim among them. On the lake side of the walk several round ice disks spin with the wave action. The turning disks contact other disks or rocks and wear down any sharp edges. I can see the disks growing in size as small pieces of floating ice adhere to the outside of the disk. Red-breasted Mergansers float in the waves out in the big lake. A stiff wind blows and we don’t dare stand in the open too long at these temperatures. We flee back to the warmth of the truck.

Otter slide and tracks

At Loud Dam we see a hundred Trumpeter Swans below the dam. I hear them call as I get out of the truck. Trumpeter Swan recovery is one of the greatest conservation stories. In 1933 only 66 Trumpeter Swans existed in the 48 states, fewer than I have in my current view. They are a common sight now in the Grayling area and we find one or two nests every year without searching. Buffleheads, Goldeneyes, Mallards, Common Mergansers are mixed in with the swans. David Sibley has some helpful tips for separating Trumpeter Swans from Tundra Swans.

Trumpeter Swans

Ice crystals form unique patterns at these temperatures. We find pretty crystal shapes along small streams and at the edge of the river.

Ice Crystals

We spent the day wandering through Nature even though the temperature never reached zero. We dressed for it and knew when to seek shelter from the wind. Despite the lack of a Snowy Owl it was a fun day. There are things to see outdoors in Michigan no matter the season. Get out and look.

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The Michigan Nature Guy’s Blog

To get people looking at, enjoying, and understanding the natural world around them.

Why do some Trees Lose their Leaves for the Winter?

Running Ground-pine in Michigan

A Cockroach, a Beetle, and a Fly

How to Identify Wildflowers

Beach-Heath

A New Michigan Fern Book

Sweet Gale: an often overlooked shrub

Labrador-tea

Boxelder Bugs

Snowy Owl Quest