Plant Profile: Wild Geranium

Wild geranium (Geranium maculatum) is a native, herbaceous perennial of open woods and woodland edges. It begins blooming in May, about the same time as Trillium, with loose clusters of pink to lavender flowers at the ends of hairy stems. The plant is also called wild cranesbill or storksbill for the long, beak-like capsules produced after flowering.

In the flower on the left, the inner ring of anthers is releasing pollen.

The stigma is not yet mature. On the right, the anthers are past maturity

and the curled, five-parted stigma accepts pollen.

The anthers in a flower mature first – an outer ring and then an inner ring – followed by the stigma of the pistil, a sequence that favors cross-pollination (1). A variety of bees, flies and beetles visit the flowers for nectar and pollen, guided, or maybe lured, by the lines on the flowers’ petals. Larvae of several insects also feed on the plant (1).

Collecting seeds from wild geranium can be tricky. As a capsule matures and dries, each of its five parts separates from the central column and curls upward, flinging the seed from the oval chamber at the base. To catch the seeds, it's best to collect the capsules when they just begins to change color. Put them in a closed paper bag to dry and release its seeds. 

The seeds need a period of cold, moist conditions before they will germinate, so either sow them outdoors in fall or treat them artificially (2). Instructions are available from Prairie Moon Nursery, prairiemoon.com.

Left: A nymph of the Fork-tailed Bush Katydid (Scuddaria furcata) visits a Wild Geranium flower. Right: A Thick-headed Fly (Myopa species) sips nectar.

Wild geranium also reproduces vegetatively. Thick rhizomes produce patches of plants that can be divided, ideally in spring or fall. Cut the rhizomes where they make right angles (2). Of course, don’t harvest rhizomes on public land or on private land without permission.

Immature (left) and post-mature (right) capsules of Wild 

Geranium. Seeds have already been released from the 

capsules on the right.

A few plants have leaves that look like wild geranium. Sanicles, also called black snakeroots (Sanicula species), grow in a similar habitat but have alternate leaves on the stem, in contrast to the opposite leaves  of wild geranium. Also unlike wild geranium, Sanicle stems and leaves have no hairs (5). Canada anemone (Anemone canadensis), usually found in wetter habitats than wild geranium, has leaves with sharper teeth (3). Like wild geranium, its stems are hairy, but the hairs are spreading or ascending. In contrast, the hairs on the stems of wild geranium point downward (5)

 

Wild Geranium spreads vegetatively by rhizomes. The largest

one is about as thick as a thumb.

References

(1)    Pollinators of Native Plants, by Heather Holm. Pollination Press, Minnetonka, MN. 2014.

(2)    Wild Geranium, Geranium maculatum. Wisconsin Horticulture, Division of Extension. University of Wisconsin-Madison. Website accessed May 31, 2021. https://hort.extension.wisc.edu/articles/wild-geranium-geranium-maculatum/

(3)    Geranium maculatum (Wild Geranium). Minnesota Wildflowers. Website accessed May 31, 2021. https://www.minnesotawildflowers.info/flower/wild-geranium

(4)    USDA, NRCS. 2021. The PLANTS Database (http://plants.sc.egov.usda.gov, 05/28/2021). National Plant Data Team, Greensboro, NC USA.

(5)    Flora of the Great Plains, by the Great Plains Flora Association. University Press of Kansas, Lawrence. 1986. 

The Pretty Problem of Siberian Squill

Siberian Squill (Scilla siberica) is an introduced plant that blooms in early spring. Leaves are basal, up to six inches long and 1/2 inch wide. Flowers are blue on leafless stalks. This ephemeral plant dies back in late spring. 

Siberian squill is a beautiful, eye-catching plant. Its bright blue flowers are among the first to bloom in spring, providing a pop of early color in gardens, lawns and woodlands. To many who are winter-weary, it's a welcome sight.

Lately, though, the plant is getting attention for a different reason. The same qualities that have long made Ssquill popular – its profusion of flowers, its tendency to spread into masses, its easy propagation – have also raised suspicions that it can be invasive. In some places, squill has jumped the garden border or the naturalized planting to grow where it wasn’t intended. That includes deciduous forests, where there is rising concern that it can displace native woodland plants.

It has taken a long time, and some long-distance travel, to get here. Squill is thought to have arrived in the United States in the late 1700s, when it was imported from its native range in southwest Russia and the Caucuses [1].  Promoted as an ornamental, it reached the Midwest by the mid-1900s. The first record of squill in the Wisconsin State Herbarium [2] is a plant collected in 1955 from Hortonville, in eastern Wisconsin. Later herbarium records find it at Point Beach State Forest near Manitowoc in 1964, the campus of UW-Oshkosh in 1966, and Turville Woods, west of Milwaukee, in 1975.

Squill reached Minnesota sometime later. The garden census for the Eloise Butler Wildflower Garden has counted squill among its numbers since 1985 [3]. The earliest herbarium records from the Minnesota Biodiversity Atlas [4] are dated 1997, when squill was found in Forestville State Park, and 1999, when it was found in Frontenac State Park, both in southeast Minnesota. Today squill is found throughout much of the state.

Judging from records of its distribution, squill can live quite well outside tended plantings. Freed of any apparent constraints, it can reproduce quickly by bulbs and seeds to form potentially large populations. A sample of EDDMapS reports [5] gives some idea of its ability to spread: 7 square feet of cover in a Rochester park; 800 square feet in a park in Maple Grove; an acre – about 43,000 square feet – in the Roberts Bird Sanctuary in Minneapolis, where squill escaped from a garden into an adjacent woodland reserve.

According to these reports, not all wild populations are (yet) large and dense, but there are more clues this can happen. In fact, some people want it to happen. For example, many gardening websites and advertisements picture broad expanses of squill, wide carpets of blue below an overstory of handsome trees. Far from being a red flag, squill’s habit of spreading is viewed as positive. If the pictures don't say it, the words that accompany them do: “Great naturalizer,” proclaims one advertisement. “Best when planted in large drifts,” advises another. One more takes that advice a step further: “Mass in sweeping drifts in woodland, wild or naturalized areas.”

The fear, again, is that sweeping drifts of squill could broom other plants out of existence. Several native spring wildflowers – bloodroot, wild ginger, Trillium, Hepatica, spring beauty, and others – share a similar woodland habitat and phenology, and they may be unable to compete with an aggressive introduction like squill. Proof of harm needs formal research, but until any such studies are complete, informal studies, reports, and observations are raising concerns.

Suspicions are now great enough that leaders in the gardening world are urging caution. The University of Minnesota Extension Service [6] warns that although squill is beautiful, it may be harmful. “Because of its rapid spread and condition tolerance,” they write, “this non-native species has the potential to become an invasive plant.”

At the Minnesota Landscape Arboretum, managing squill has become a struggle. Gardeners there are frustrated by the difficulty of establishing other plants where squill has spread. One gardener tried digging out squill and planting wild ginger. Unfortunately, two years later squill had rebounded and the wild ginger was all but gone [9].

The Southeast Wisconsin Invasive Species Consortium [7] is also wary. Calling squill “a classic case of gardening gone awry,” the group is alert to the probability of trouble. Citing the plant’s cold hardiness and unpalatability to deer and other herbivores, they lament the consequences of its popularity: “Sadly, the same traits that make it attractive as a garden plant . . . are also what make it invasive.”

 

Understandably, fans of squill find this hard to accept. A lively debate on the Minnesota Wildflowers website includes defenders who like the plant for its beauty, its role as a harbinger of spring, and its sentimental value. Some assert that the plant is well-behaved and is a food source for pollinators. Others want proof that squill displaces native plants.

 

The debate goes to the heart of invasive species biology. Many plants are introduced because, like squill, they're beautiful. People plant them because they admire them. Most of these species cause no harm to natural areas. Marigolds, petunias and impatiens, for example, usually stay put. A few introduced species, though, have it in them to spread. They might limp along for a while, but eventually they gain enough of a toe hold to dominate a landscape, whether it’s a garden, a yard or a natural area. 

Increasingly, squill appears to be one of those runaway species. Some gardeners and natural area stewards have spent years trying to remove squill from garden plots, lawns and woodlands, and their frustration is clear. So are their warnings. They advise removing squill when its populations are small and easier to take out. Better yet, they say, avoid the problem by not planting it at all. 

Proof of harm to native plants and pollinators will take time to complete. If studies confirm that squill is invasive, it will be years before that evidence is published. In the meantime, it's clear from a growing number of observations that squill as an emerging concern. As one gardener at the Arboretum put it, “It’s beautiful, but it’s very invasive. When it naturalizes too much, it’s difficult to get rid of.” [8]

 

Squill is indeed beautiful. This unique plant reminds us of spring and perhaps of those who planted the bulbs with good intentions of creating a pleasing landscape. However, if we’re on the cusp of recognizing that squill can be harmful, now is the time to act. In some places, at least, this pretty plant has become a big problem.

 

Squill Removal and Look-Alikes

Removing Squill can be a tough job, especially if it’s growing in masses. For tips, scroll through the discussion on Minnesota Wildflowers and see the advice from the University of Minnesota Extension Service [6].

 

Squill is easiest to recognize when it’s flowering, but it has some look-alikes.

 

Harebell (Campanula rotundifolia) has bell-shaped, purple flowers on leafy stems reaching 20 inches tall. Typically, it grows in dry, open places. It blooms in summer.

 

Blue-eyed Grass (Sisyrinchium species) has grass-like leaves and dark to pale purple flowers with yellow centers and yellow anthers. Squill has blue anthers. Three species grow in Minnesota, all in sun. They bloom from May to July.

 

Like Squill, Spring Beauty (Claytonia virginica) is a woodland spring ephemeral. It blooms a little later than Squill and has pink-veined flowers. Flowering stems bear long, narrow leaves.

From left: Spring Beauty, Harebell, and Mountain Blue-eyed Grass, Sisyrinchium montanum.
Harebell photo copyright 2008 Katy Chayka. Blue-eyed Grass photo copyright 2012 Peter Dzuik. Both photos are from Minnesota Wildflowers.

 

 

References

[1] Flora of North America. Scilla siberica. Website accessed May 2021.

 

[2] Consortium of Midwest Herbaria, midwestherbaria.org. Accessed May 2021.

 

[3] The Friends of the Eloise Butler Wildflower Garden. Blue Squill, by G.D. Bebeau. 2015. Accessed May 2021.

 

[4] Minnesota Biodiversity Atlas. University of Minnesota Bell Museum. Accessed May 2021.

 

[5] EDDMapS. 2021. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org; last accessed May 7, 2021.

 

[6] University of Minnesota Extension Service. Squill, by Angela Gupta, Amy Rager and Megan Weber. Reviewed 2021.

 

[7] Southeastern Wisconsin Invasive Species Consortium, Inc. (SEWISC).  Siberian Squill. Website accessed May 2021.

 

[8] Pretty, but aggressive squill, by Erin Buchholz. Nature Notes. News from the Minnesota Landscape Arboretum. May 13, 2020.

 

 

 

 

Bloodroot's Bet

This herbaceous perennial is among the first to bloom on the deciduous forest floor. It's also among the hardiest.

Bloodroot, Sanguinaria canadensis, in early April 2021.

Every year, bloodroot throws the dice. It blooms surprisingly early, risking the return of winter weather to grow and flower when light intensity is highest on the deciduous forest floor. Its way of surviving in shade is to mostly avoid it, and thanks to several adaptations to cope with the uncertain conditions of early spring, it has succeeded.

Sometime in late March or early April, single basal leaves spear through the leaf litter, wrapped around and protecting flower stalks bearing one, delicate bud. On dry, sunny days, the flowers open like bowls, each a brilliant display of eight or more petals around a mass of orange-yellow stamens and a central pistil.

Little else is blooming at the time, so bloodroot doesn’t have much competition for the few pollinators that are active in early spring. Although bloodroot has no nectar, insects nevertheless circle over the flowers in search of a sugary sip.  A few will land inside, and over the course of a few days, they will find that Bloodroot’s offerings change.

When a flower first opens, only the stigma is mature. The anthers need another day or two before they’re ready to release any significant amount of pollen. Although visiting insects won’t find much pollen to gather from a young flower, they can deliver what they collected from an older one. In rapid succession, the stigma receives the pollen, the eggs are fertilized, and seeds begin to develop. Such cross-pollination has the advantage of mixing genes from different plants, creating new combinations that might improve offspring survival.

Self-pollination isn’t likely to occur at this stage, in part because the anthers aren’t mature but also because the stamens initially bend away from the pistil. By day three in a flower’s life, however, the anthers are fully developed and the stamens change their position. Instead of bending away from the pistil, they bend toward it, increasing the odds that the flower will fertilize itself.

Left: In recently-opened flowers, the stamens and immature anthers bend away from the pistil.
Right: In an older flower (three days or so), the stamens bend toward and even arch over the pistil.

In a sense, this is bloodroot’s life insurance policy. If cross-pollination doesn’t happen – say in a stretch of cold, rainy or snowy weather that limits pollinator activity – self-pollination is a fallback. The resulting seeds will produce offspring much like the parent, but at least there will be seeds, tiny propagules that can be disseminated to expand the population.

Whatever ate these Bloodroot leaves might not have
enjoyed them for long. Bloodroot sap contains several
alkaloids, bitter molecules that can be harmful.

Of course, insects aren’t the only animals looking for food in early spring. Hungry herbivores are also on the prowl, and bloodroot provides some tempting, tender shoots. One chomp and bloodroot could lose its annual opportunity to grow and reproduce. The “blood” of bloodroot tends to discourage that activity, however. It contains several alkaloids, molecules that are distasteful if not harmful to animals that eat them. Alkaloids are most concentrated in the roots, but they are found in all parts of the plant, including the leaves and petioles. A mouthful of the bitter greens could be enough to put an herbivore off bloodroot for a long time.

It’s a gamble to grow early, but bloodroot has adapted to the risk. The plant's fragile appearance belies a durability born of countless generations on the forest floor. Through genetic trial and error, the dice came to be loaded in its favor.     

References

Hayden, W.J. (2005). Bloodroot pollination: Bet-hedging in uncertain times. Bulletin of the Virginia Native Plant Society 24(1): 5+

Matsuura, H., & Fett-Neto, A. (2015). Plant Alkaloids: Main Features, Toxicity, and Mechanisms of Action.

Schemske, D.W., Willlson, M.F., Melampy, M.N. et al. (1978). Flowering ecology of some spring woodland herbs. Ecology 59 (2): 351-366.

Hopeful News About Emerald Ash Borer

 “Attack fungi” could help manage this destructive insect.

University of Minnesota researchers recently discovered insect-attacking fungi in the larval galleries of emerald ash borer. Their finding offers hope that the fungi could help manage this destructive pest.

Emerald ash borer (EAB) is an introduced beetle that kills all species of ash trees. It has been present in the U.S. since at least 2002 and in Minnesota since at least 2009. Even with a federal quarantine (now removed), the insect spread rapidly. According to the USDA, its range now covers most of the eastern U.S. and the Midwest, with isolated infestations as far west as Colorado.

The larvae of EAB cause the bulk of the damage. After eggs hatch, the larvae bore into the inner bark, the area that includes the water- and sap-conducting cells of the xylem and phloem. Their galleries of serpentine tunnels interfere with the flow of needed resources and kill trees in 2-4 years. Hundreds of millions of trees have succumbed to the insect.

Hope for managing EAB rests in part on biocontrols, organisms that prey on eggs, larvae or adults and so reduce their numbers. Three parasitoid wasps have been released in Minnesota as potential biocontrols. More information about that program is available here.

New biocontrols could emerge from recent research by the Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC). In their study published in Fungal Biology, U of M researchers sampled affected trees from Rochester to Duluth and isolated the fungi associated with EAB larval galleries. They identified many types of fungi, including some that are entomopathogenic – fungi that attack insects.

One fungus they identified, Beauveria bassiana, has already been studied for EAB control. The other entomopathogenic fungi they found also need research to see if they, too, could be used to manage the insect.

This good news comes as EAB continues to spread in Minnesota. Since the November 2020 post about EAB, the insect has been confirmed in two more counties, Cottonwood and Blue Earth in southwest Minnesota. The state’s Department of Agriculture maintains a quarantine boundary that now includes 27 affected counties. 

Quaking Aspen Breaks the Ice

 

If you’re eager to see something in bloom, look for quaking aspen (Populus tremuloides). In southern Minnesota, the tree’s flower buds broke in early March and the flowers are almost mature. Don’t expect to see anything showy, however. Early bloomers like quaking aspen tend to be wind pollinated. There aren’t many insects around yet, so they don’t produce large flowers with colorful petals. Instead, quaking aspen produces dozens of tiny flowers on small spikes called catkins.

This is a lengthwise section through a catkin of male flowers. 

Each flower is just a few millimeters wide, composed of a light 

yellow cup, a brown bract with finger-like lobes and hairs, and

stamens. The red "bumps" are developing anthers.

This photo was taken on March 22, 2021.

The only flower parts you might see, if you look closely, are stamens or pistils. Individual trees usually bear only one kind of flower. In other words, trees are either male (pollen-producing) or female (seed-producing). Both male and female trees flower before leaves emerge, timing the wind-driven spread of pollen when there is the least interference.

You might also notice that all or most of the trees in a stand of quaking aspen bloom at the same time. That’s likely because they’re clones. Quaking aspen reproduces vigorously by root suckers, with young plants emerging amid or around a stand of older trees. All individuals in a clone are connected by a common root system and are genetically identical. In a sense, they are one being. 

The stand pictured here, found in western Hennepin County, covers about 2,000 square feet. Most of the trees in the stand bloom at the same time, so they probably belong to the same clone. In other words, that’s one organism covering 2,000 square feet. That’s big, but it’s far from the biggest clone of quaking aspen. A stand in Fishlake National Forest in central Utah, called Pando (Latin for “I spread”), comprises more than 40,000 individuals, all male, together covering 106 acres and weighing an estimated 13 million pounds. Pando was once the largest known organism on Earth, and one of the oldest. Although its exact age is uncertain, the stand is thought to have originated at the end of the last glacial period, about 11,000 years ago.

Unfortunately, Pando may be declining. Scientists have noticed that the stand is producing fewer young trees. Grazing and browsing of root suckers is one possible reason, but diseases, insects and lack of disturbance, which favors vegetative reproduction, may also be causes. Efforts are underway to understand why the stand isn’t regenerating and to slow or prevent its further decline.

Far from Utah, in this small stand of quaking aspen, female trees will soon be pollinated and release their cottony seeds. Like the pollen, the seeds are carried by wind, and in a month or so there will be a blizzard of them. If they happen to land where soil is moist – even for just a few hours – they will germinate and an infant stand may be born. It’s a chancy way of reproducing, but even Pando started this way. Big clones from little aspen seeds grow.

References

The Diminishing Pando Clone: History and Forest Management
https://history.utah.gov/the-diminishing-pando-clone-history-and-forest-management/
 
Pando – (I Spread)
https://www.fs.usda.gov/detail/fishlake/home/?cid=STELPRDB5393641
 
Smith. W.R. 2008. Trees and Shrubs of Minnesota. Minnesota Department of Natural Resources. University of Minnesota Press, Minneapolis.

The Two Lives of Cedar-Apple Rust

 

The dimpled, red galls on this eastern red cedar (Juniperus virginiana) are signs of cedar-apple rust, a fungus that divides its time between two completely different hosts. One part of its life cycle is completed on junipers, where these golf ball-like masses can be spotted in winter. The other part is completed on plants in the rose family, such as apple trees. On each host, the appearance of the fungus is so different that it can be hard to connect the two as belonging to the same organism.

In spring, cedar-apple galls on junipers sprout gelatinous, orange “horns.” These gummy tentacles produce and release spores that can infect the leaves of apples, crabapples and sometimes hawthorns. As the fungus grows on apple trees, the leaves develop yellow or orange spots on their upper and lower surfaces. In summer, spores released from the spots on the lower surfaces of the leaves are spread by wind back to junipers, where they form overwintering galls. And so the cycle is continues.  

Left: Cedar apple gall with orange, spore-producing "horns" in spring. Right: Spots on an apple leaf caused by the cedar-apple rust fungus. Spores produced on apple leaves then infect junipers.

Photos by James Chatfield, Ohio State University, Bugwood.org, through forestryimages.org.

Cedar-apple rust usually doesn’t have severe effects, although infection can cause susceptible apples and crabapples to lose their leaves early. Fruits may also develop unattractive spots. Many varieties of apples and crabapples are resistant to cedar-apple rust. For a list, see the University of Minnesota Extension Service link below.

Spots on apple leaves can also be caused by other fungi. Apple scab is one example.

References

Cedar-apple rust and related rust diseases. R. Koetter and M. Grabowski, University of Minnesota Extension Service.  Accessed online 2/27/21.

Plant of the week: Cedar apple rust (Gymnosporangium juniperi-virginianae Schwein.). D. Taylor, U.S. Forest Service. USDA. Accessed online 2/27/21.

Agrios, G. N. 1988. Cedar-Apple Rust. Pages 462-466 in Plant Pathology, third edition. Academic Press, Inc. New York.

Crusty Clues to Plant ID

In this patch of winter woods, black knot has a grip on the understory. Dark, lumpy galls crust over many stems and branches, flagging them against the snow. From a distance it looks like scat, but this isn’t animal stuff. It isn’t plant stuff either, not entirely. It’s a fungus, and it’s dropping hints about the plants growing here.

Many fungi that grow on plants, including black knot, have specific hosts. Some grow so consistently on one plant or another that when they’re found, they can help identify a plant to its genus, if not its species. This can be especially helpful in winter, when plant ID is challenging without leaves.

Many fungi serve as reliable guides to plant identification, but here are three that are especially common or commonly sought and easy to recognize.

Prunus and Black Knot

Black knot, Apiosporina morbosa, infects trees and shrubs in the genus Prunus, a group that includes native and introduced cherries and plums. In Minnesota, the disease is especially common on chokecherry, Prunus virginiana, a small tree found in open woods and woodland edges throughout the state. It also affects American plum (P. americana), Canada plum (P. nigra), pin cherry (P. pensylvanica), black cherry (P. serotina) and sand cherry (P. pumila). All these are native shrubs and trees, but several introduced species and cultivars of Prunus are also susceptible to the disease.

Black knot is spread in spring, when fungal spores produced in these knots are carried by wind or rain to new hosts. A year later, after the fungus has stimulated its host to grow a mass of large cells, the infection appears as a swelling with a light brown or olive-green surface. In the second summer after infection, the gall turns black. Some galls may have white or pink patches on the surface from other fungi parasitizing the knot.

Tiny pores on the surface of a gall mark the exit holes for spores. They’re easiest to see with magnification. Pores are one way to distinguish black knot from chaga, a similar dark, crusty fungus that grows primarily on birch trees. Unlike black knot, chaga is sterile -- it doesn't produce spores. More on that next. 

Birch Trees and Chaga

Chaga, Inonotus obliquus, is a parasitic fungus found in northern forests around the world, including the United States and Canada. It has been used in folk medicine for centuries and is still harvested and consumed for its purported health benefits. Formal studies of its medicinal use continue.

In this region, chaga grows mostly on birch trees, especially paper birch, Betula papyrifera. It also grows on yellow birch, Betula alleghaniensis, and much less frequently on alders, beech, oaks, maples and aspen.

On living birch trees, chaga looks like a hard, irregular, black mass erupting from the trunk. Likened to burned charcoal, the surface is a melanin-rich mass of dead fungus over an orange or brown interior. The masses, popularly called conks, appear on trunks or large branches, but not on small branches. An infected tree may bear 1-3 conks.

Chaga conks are the visible part of the fungus. The hidden part lives mostly in the heartwood, where it causes white rot. The tree may live with the infection for up to 80 years, producing slow-growing, sterile conks that take many years to mature.

Inonotus, the fungus that produces chaga, reproduces only after its host dies. The fruiting body (actually a spore-producing body called a basidiocarp) is a mat of slender, vertical tubes formed under the bark, typically above a sterile conk. As the fruiting body develops, it exerts so much outward pressure that it will suddenly rupture the bark. It’s a fascinating find, but a rare one. Fruiting bodies are produced only once in the life cycle of the fungus, and they live for just a few days.

Chaga look-alikes include black knot and several shelf mushrooms in the genus Phellinus. Unlike chaga, these fungi release spores through tiny pores. Black knot pores cover the gall, wheareas shelf mushrooms have a pore layer on their lower surfaces. 

A note about harvesting chaga:

Because of its purported medicinal value, chaga is in high demand, so harvest from some public lands is regulated. According to Ed Quinn, Natural Resource Program Supervisor for the Division of Parks and Trails at the Minnesota DNR, harvesting chaga is illegal in state parks, state recreation areas, state monuments and state waysides. Although state park rules permit collection of­­­­ mushrooms for personal use, chaga is technically not a mushroom because it isn’t a fruiting body -- it doesn’t produce spores. In addition, use of spikes, ladders, knives and hatchets to reach and collect the fungus can damage trees and create wounds that may leave them vulnerable to pathogens and insect pests. Finally, because the fungus slowly rots the heartwood of infected trees, climbing them can be unsafe.  

The rules in state forests differ from those in state parks. According to Dave Schuller, State Land Programs Supervisor for the Division of Forestry at the Minnesota DNR, collecting chaga for personal use is allowed without a permit, but host trees must not be damaged. Commercial harvest is allowed with a special products permit from a local DNR forestry office. The permit requires harvesters to take only the visible part of the fungus, without cutting into the stem or damaging live trees. More information about chaga harvest is available from the University of Minnesota Extension Service publication linked in the references below. Again, safety is paramount when harvesting chaga. Because trees bearing the fungus may have significant interior decay, climbing them is risky and can result in serious injury. 

Harvesting chaga on other public lands, such as regional or local parklands, may also be regulated. Check with the appropriate authority before heading out.

There are also concerns about the potential effects of collection on chaga biology and ecosystem health (Thomas et al., 2020). One issue is that overharvesting chaga has unknown effects on the ability of the fungus to reproduce. Taking too much, too often could delay or deny Inonotus its once-in-a-lifetime opportunity to make fruiting bodies, with consequent effects on its spread.  

Overharvesting also has unknown effects on the function of ecosystems where chaga is found. Other living things – insects, for example – may depend on chaga in ways not yet understood. Without that understanding, aggressive collection of chaga could have ripple effects on ecosystem health. More study is recommended.

 

White Oaks and Smooth Patch

Smooth patch looks like it sounds: It’s a smooth patch on otherwise rough bark. Usually the area is low on the trunk and sunken and lighter than surrounding bark. Smooth patch disease is caused by any of several fungi, especially Aleurodiscus oakesii. This fungus prefers trees in the white oak group, In this region the most common hosts are white oak, Quercus alba, and bur oak, Quercus macrocarpa. Less often, smooth patch is also found on birch, ash, willow and basswood.

The fungi that cause smooth patch feed only on dead outer bark and don’t directly harm the tree. Small, cup-like fruiting bodies are often seen within the smooth patch. They are light brown or gray with curled edges. In winter they may be shriveled and look like lichens. The genus Aleurodiscus translates to “flour disc,” named for the whitish, dusty appearance of the disks in spring and summer.

 

References

Black knot

American Phytopathological Society. Black knot. Website accessed February 11, 2021.

University of Illinois Extension, Department of Crop Sciences, University of Illinois at Urbana-Champaign. Black knot of plums and cherries. RPD No. 809 September 2000.

University of Minnesota Extension Service. Black knot. Website accessed February 11, 2021.

Chaga

Millman, L. 2012. Chaga’s Significant Other. Fungi 5:3, 11-12.

Min-Woong Lee, Hyeon Hur, Kwang-Choon Chang, Tae-Soo Lee, Kang-Hyeon Ka, L. Jankovsky. Introduction to Distribution and Ecology of Sterile Conks of Inonotus obliquus. Mycobiology. 2008 Dec; 36(4): 199–202. Published online 2008 Dec 31. doi: 10.4489/MYCO.2008.36.4.199

Natural Resources Canada. Sterile conk trunk rot of birch. Date modified:2015-08-04. Website accessed February 11, 2021.

Spinosa, R. and Bunyard, B. No, That’s NOT Chaga! Fungi 5:3, 45-47

Thomas P.W., Elkhateeb W.A. & Daba G.M. 2020. Chaga (Inonotus obliquus): a medical marvel becomes a conservation dilemma? Sydowia 72: 123–130.

University of Minnesota Extension Service. 2013. Chaga (Clinker Polypore). Pages 99-101 in the Minnesota Harvester Handbook. Available at https://conservancy.umn.edu/handle/11299/173824.

Smooth patch of oak

Smith, W. R. 2008. Quercus macrocarpa Michx., Bur oak. Pages 382-383 in Trees and Shrubs of Minnesota. Minnesota Department of Natural Resources. University of Minnesota Press, Minneapolis.

University of Minnesota Extension Service. Non harmful tree conditions. Website accessed February 11, 2021.

Vann, S. R. Undated. Smooth patch of oak trees. FSA7578, University of Arkansas, Division of Agriculture.

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