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Written by: Mary Anne Young
What’s not to like about a plant that flowers while other plants are shutting down for the season?
American Witch Hazel (Hamamelis virginiana), is an understory shrub of North America’s eastern deciduous forests. Although it does have interesting wavy leaves which add character in the forest, or woodland landscape design, throughout the summer, its real beauty is in the late fall when its yellow fall colour drops and it begins to bloom. Few native plants in North America flower in this season, so it is always a delight to me to find a Witch Hazel in full bloom when other plants are winding down for the winter.
The flowers are unique, consisting of twisted thread-like petals with a pleasant scent. It also has an interesting seed dispersal mechanism where the woody seed capsules slowly mature over the course of a year and when it dries to a certain extent splits open to shoot 1-2 black seeds explosively up to 6m (20 feet) in every direction.
Here are some additional details about this fascinating species:
Form: Woody plant, medium to large shrub
American Witch Hazel(Hamamelis virginiana)
Understory shrubs of the eastern deciduous forest have a tendency to be overlooked in favour of the delicate spring flowering wildflowers underfoot, or the towering trees overhead. However I challenge you to keep an eye out for Witch Hazel this fall as it puts on a show unrivalled by other forest plants at this time of the year. |
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Written by: Carl-Adam Wegenschimmel
One of the greatest adversaries to garden and wild plants is the great host of pathogens that regularly attack them. These organisms can belong to a variety of groups, including; fungi, bacteria, nematodes, and viruses. As human beings, we often consider the economic costs these organisms have on our economy, particularly in the agricultural, garden, and forest industries. However, pathogens also play natural roles in our ecosystems, killing sick plants and controlling the population growth of certain species that could otherwise dominate a community.
With the growing concern and insight into climate change, understanding how these understudied groups may affect plants and ecosystems is becoming increasingly important. One of the most noticeable of these groups is fungi!
Fungi attack their plant hosts in a variety of ways, some may first kill their hosts and feed on dead material (necrotrophs), which enter their hosts through wounds and natural openings. Other fungi feed on living tissue (biotrophs) which often enter their hosts in more specialized ways (Doehlemon et al. 2017).
Necrotrophs can sometimes be very destructive, especially when they are invasive species. A well-known example is Dutch Elm Disease (Ophiostoma novo-ulmi), which has severely reduced Elm tree abundance in North America. In this case, the fungus attacks trees with the aid of insects like the Native Elm Bark Beetle (Hylurgopinus rufipes) and the introduced European Elm Bark Beetle (Scolytus multistriatus). Dutch Elm Disease is believed to have originally been introduced from Asia, and so our native Elm trees have evolved little resistance to the fungus (Hubbes 1999). American Elm (Ulmus americana) and Rock Elm (Ulmus thomasii) have suffered the worst with Red Elm (Ulmus rubra) being slightly more resistant. The disease is spread to Elm trees when the beetles feed on twigs in spring time entering and slowly spreading into the trunk of the trees, blocking vascular tissues and eventually killing the host. The beetles are attracted to the diseased elms for breeding and subsequently bore holes into the infected Elms. Eggs are laid inside infected Elms where newly hatching beetles pick up spores and continue the cycle.
Biotrophic fungi require living hosts in order to feed and have evolved specifically to interact with a living organism rather than a dead one. One of the most visible groups of these plant parasites are the rust fungi, which is one of the largest orders of fungi containing more than 8000 species worldwide (Lorrain et al. 2018). Some rusts cause little damage to their hosts whereas other species are better referred to as hemibiotrophs, which start off as seemingly benign biotrophs but eventually kill their host and act as necrotophic fungi (Koeck et al. 2011).
Some hemibiotrophic rusts are known to cause devastating damage to crops.
There is still much to learn about the complex interactions between fungal pathogens and their plant hosts. Although with the continuous increase in scientific knowledge and technology, our understanding of these interactions is becoming clearer. Citizen science apps (like EDDMapS Ontario and iNaturalist) have also helped document the occurrence of these species, and may serve to help record the distribution of invasive species and maybe even prevent the spread of early invasions.
References
Doehlemann G, Ökmen B, Zhu W and Sharon A. 2017. Plant Pathogenic Fungi. Microbiol Spectr. 2017 Jan;5(1).
Hubbes M. 1999. The American elm and Dutch elm disease. Forest. Chron. 75:265–273.
Koeck M, Hardham A. R. and Dodds. 2011. The role of effectors of biotrophic and hemibiotrophic fungi in infection. Cell Microbiol. 2011 Dec; 13(12): 1849–1857. Published online 2011 Sep 14.
Lorrain C, Gonçalves dos Santos K.C, Germain H, Hecker A and Duplessis S. 2018. Advances in understanding obligate biotrophy in rust fungi. New Phytologist (2019) 222: 1190–1206.
Sutherland R, Hopkinson S and Farris S.H. 2011. Inland spruce cone rust, Chrysomyxa pirolata, in Pyrola asarifolia and cones of Picea glauca, and morphology of the spore stages. Canadian Journal of Botany 62(11):2441-2447 · January 2011
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Written by Carl-Adam Wegenschimmel
The theme of this year’s World Wildlife Day celebration is “Sustaining All Life on Earth,” which recognizes biodiversity as a key component in protecting natural life.
To this end, it is important to acknowledge all species, including those that are often ignored or seen as not having any economic value to humans. We need to take a holistic perspective and recognize the interconnectedness of all living things. Although many plants are valued by people, many other species remain ignored but nonetheless have intrinsic worth and act as key components of ecosystems.
Here in Canada, we are still discovering and learning about our own plant communities. During Ontario Botanists' Big Year 2019 on iNaturalist, Kevin Gevaert discovered a plant that is new to Canada: Slender Three-seeded Mercury (Acalypha gracilens) -- surprisingly within the urban boundary of Caththam-Kent.
This past fall, while I was out exploring a section of the Niagara Escarpment with fellow ecologists Tristan Knight and Jose Maloles, Tristan discovered a moss growing on the cliff face which he identified as Fan Moss (Forsstroemia trichomitria). This species was rediscovered in Quebec in 2011 after not being seen in North America since the late 1800s. Since then, it has only been observed once in Ontario and once in Quebec.
Photo by Carl-Adam Wegenschimmel
Tristan’s discovery marked the second modern record for Ontario and fourth extant record in North America.
Jennifer Doubt, a botanist at the Canadian Museum of Nature in Ottawa, is currently documenting Fan Moss distribution and abundance in Canada, to help understand its conservation status.
Another recent discovery in northeastern North America is the Tall Beech Fern (Phegopteris excelsior), seen for the first time in 2019. Although it hasn’t been documented in Ontario yet, I believe it is only a matter of time before some keen observer is able to separate it from the closely-related and better-known Broad Beech Fern (Phegopteris hexagonoptera).
I am often amazed in the ability of healthy, mature forests and plant communities to support substantial fungi and lichen communities, with many species still completely under the radar. Here too, there are likely many discoveries yet to be made.
For example, while recently exploring a swamp in Hamilton, I found a species of Chaenothecopsis fungi growing on Paper Birch (Betula papyrifera) which appears to be new to science based on previous collections in Ohio. Another new species of lichen was recently discovered in swamps near Toronto, a stubble lichen (Chaenotheca selvae), which seems to have an affinity for stumps of mature Maple trees.
Photo by Carl-Adam Wegenschimmel
I think that these discoveries underscore how much we have yet to learn, even in places that are generally well-surveyed and emphasize the need to continue to study our ecosystems.
Discoveries like these also highlight the need to protect natural areas, which maintain biodiversity at both the local and global level.
Many wildlife observations today come from citizen science initiatives, which gather the unique experience and knowledge of individuals into centralized databases. These include eBird, created by Cornell University and the Audobon Society, and iNaturalist, offered by the California Academy of Sciences and the National Geographic Society.
These apps make it easy for anyone to contribute to our understanding of biodiversity. This can create newfound appreciation and positive momentum towards sustaining our natural world. One of our big dreams for CanPlant is to use this kind of technology and public participation to enhance our understanding of Canadian plants and landscapes.
Are you an intrepid botanizer who would like to participate in CanPlant's work? You can use our Submit a Photo form to contribute your plant photos, or Contact Us directly if you have a larger collection you'd like to share.
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Written by: Nicole White
People used to view wetlands as a waste of space: they can't be built, they can't be easily traversed by boat, and they aren't profitable for most types of agriculture. So why are wetlands so important?
Now we're learning that wetlands are some of the most biologically productive sites on our planet. They hold water in times of flood or drought, purify the environment, and sequester carbon from the atmosphere. I've heard them called 'Nature's Kidneys'. They sustain life by providing essential year-round or seasonal habitat for many species of fish, birds, and other animals. They are also home to plant communities found nowhere else, and have a breathtaking beauty all their own.
Events like World Wetlands Day (Sunday, February 2) work to shift these attitudes, and effect change.
As a small celebration of World Wetlands Day, I conducted an informal poll of my ecologist colleagues to find out what everyone's favourite wetland plant was. The results were fun and I hope our appreciation of these plants inspires you to learn more about them:
We hope you're inspired to learn more about the strange and wonderful plant life growing in our country's wetlands. Check out the links below, or visit the CanPlant Search Page to discover more species.
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CanPlant Blog 18 January 4, 2021 |
Other species of rusts are rarely seen but have complex lifestyles like Chrysomyxa pyrolae seen here (right) on American Pyrola (Pyrola americana), which cycles between its Pyrola and Spruce (Picea spp.) hosts. Although this species does not necessarily kill its hosts, it has been observed to negatively affect seed crop in spruce trees (Sutherland et al, 2011).
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