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Blog

Botany

Botany

09/23/22

FROM SOUTH TO NORTH: CLIMATE CHANGE IMPACT ON PLANTS

This summer I went from Manitoba’s southern-most border all the way to its northern one within just a week. I was fascinated to see how differences in climate had influenced the plant communities. The massive trees of the south give way to nearly treeless tundra in the far north. But despite being separated by over 1,000 kilometers, both places had something in common: climate change was beginning to impact the plants.

I went by motor boat to the pristine Reed River to look for rare plants. © Manitoba Museum

To the Southeast

In early August, I drove to Buffalo Point First Nation to search for rare plants, with the permission of the community. Buffalo Point is in the extreme southeastern corner of the province. Many plants reach their northeastern limit in that part of the province, including Interrupted Fern (Osmunda claytoniana).

Interrupted Fern (Osmunda claytoniana) only grows in the southeastern part of the province. © Manitoba Museum

In addition to hiking the trails there, I travelled by boat down the Reed River with two Indigenous guides. I was looking for rare plants that grow on shorelines. Alas, they were not there. Due to the heavy snow and rain this year, the water level was higher than my guides had ever seen in their lives. The water extended right into the forest, killing some of the waterlogged trees and flooding once productive beds of Wild Rice (Zizania palustris).

High water levels in the Reed River flooded areas where beds of Wild Rice (Zizania palustris) used to grow. © Manitoba Museum

To the North
A week later, I was on a plane to Churchill to search for rare plants in that part of the province. Once again, I visited a river that was swollen beyond its usual level: the Churchill River. My Indigenous guide commented that the normal shoreline vegetation was completely covered by water. But it wasn’t just the river vegetation that was being impacted, either.

Vegetation along the Churchill River was flooded in 2022. © Manitoba Museum

Another Indigenous person I met told me that her 70-year old grandfather had witnessed huge changes in the tundra around Churchill in his lifetime. Tall shrubs, like Silver Willow (Salix candida), were much less common in the past. These tall species are now increasing in abundance, as they can out-compete the short, tundra vegetation when temperatures are warmer (Mekonnen, 2021).  With continued warming, this “shrubification” will likely continue, completely changing the plant communities in the far north.

Silver Willow (Salix candida) and other tall shrubs are encroaching on the tundra. © Manitoba Museum

Climate Change Consequences

I reflected that droughts and higher air temperatures are not the only consequences of adding greenhouse gases into the atmosphere. Warm air holds more water than colder air, paving the way for unusually heavy snowfalls and torrential downpours (Konapala et al., 2020; Willett, 2020). Fewer natural wetlands in Manitoba’s south means that much of that moisture flows quickly into our rivers, causing floods, instead of being stored on the landscape. The huge Great Hay Marsh (southwest of Winnipeg), which used to cover an astonishing 194 km2, was completely drained in the early 1900’s, and no longer exists (Hanuta, 2001). It’s water storage and filtration functions, which might have helped build resiliency to climate change, are now unavailable.

The new map in the Museum’s Prairies Gallery shows the location of now extinct wetlands like the Great Hay Marsh. © Manitoba Museum

This summer was a stark reminder that the consequences of humanity’s behavior reverberates in the remotest areas of the globe. We have the ability to alter the ecosystems of the world, for good or ill. Protecting and restoring ecosystems, like wetlands, is just one way to help humanity weather the changes that are ahead.

Short, tundra plants like White Mountain Avens (Dryas integrifolia), shown here in fruit, may become rare in Manitoba, as climate change increases arctic temperatures and thaws permafrost. © Manitoba Museum

References
Hanuta, I. (2001) A reconstruction of wetland information in presettlement southern Manitoba using a Geographic Information System. Canadian Water Resources Journal, 26: 183-194.

Konapala, G., Mishra, A.K., Wada, Y. et al. (2020) Climate change will affect global water availability through compounding changes in seasonal precipitation and evaporation. Nature Communications 11: 3044.

Mekonnen, Z.A. et al (2021) Arctic tundra shrubification: A review of mechanisms and impacts on ecosystem carbon balance. Environmental Research Letters 16: 053001

Willett, K. M. et al. (2020) Development of the HadISDH marine humidity climate monitoring dataset, Earth System Science Data 12: 2853-2880.

 

07/05/22

Dandelions: Filling the Ecological Vacuum in our Lawns

You may have heard the old saying that “nature abhors a vacuum”. To understand this expression, you probably won’t need to look any farther than your own lawn. Although lawns may start out as monocultures of Kentucky Bluegrass (Poa pratensis), they never stay that way. Inevitably, species like Common Dandelion (Taraxacum officinale) show up, prompting a flurry of weeding and spraying of herbicides. We are told by lawn care companies that “healthy lawns won’t allow weeds to grow” but that statement is simply not true. Just look at any wild ecosystem in the world. Is it a monoculture with just one species? No, there are always many species. Weeds eventually invade lawns because monocultures are NOT natural. Ecosystems want to return to a natural state.

Native prairie ecosystems are natural polycultures: systems with many plant species. © Manitoba Museum

What’s really under the ground?

To help people understand the natural state of a prairie grassland, the Manitoba Museum created an exhibit called “Anchoring the Earth” in the new Prairies Gallery. This exhibit shows the root systems of native plants. Some roots are shallow, like lawn grasses, but others are deep (over 4-m!). June Grass (Koeleria macrantha) grows early in the spring, then goes dormant. Other species grow mostly at the height of summer, like Big Bluestem (Andropogon gerardi). In addition to the grasses, there are also taprooted plants like White Prairie-clover (Dalea candida). Every possible habitat or “niche” in the ecosystem is exploited by one species or another, the complete opposite of a lawn.

One of the new exhibits at the Manitoba Museum shows what native prairie ecosystems look like under the ground. © Ian McCausland

The weed you can eat

Dandelions are native to Eurasia but were introduced to the Americas. They have taproots, which grow deeper than the shallow roots of turf grasses. Dandelions exploit the nutrients and water deeper in the soil, just like the native False Dandelion (Agoseris glauca). Far from being a useless weed though, you can eat all parts of a dandelion. I’ve eaten dandelion greens in spring, made fritters with the flowers, and roasted the roots to make tea and bake a cake (when the roots are ground up, the powder is similar to cocoa). Just 100 g of raw dandelion leaves have 64% of your daily required vitamin A, 42% of your vitamin C and a whopping 741% of your vitamin K. Sometimes when life gives you lemons, you just need to make lemonade!

False Dandelion (Agoseris glauca) is a native plant with deep taproots similar to the non-native dandelion. © Manitoba Museum, H9-23-260

Lawn Origins

But why did lawns even become popular in the first place? In Europe, in the 16th century, wealthy landowners began growing lawns to flaunt their status. They didn’t need the land to grow food, they were rich enough to grow completely useless grass on their property instead! As the European middle class began to grow, they also aspired to demonstrate their wealth by growing at least small patches of lawn, if they could. This Western appreciation of the lawn aesthetic still remains with us today, but there are signs that its time is up. Concern about the impact of lawn care pesticides on human health and vulnerable pollinators has prompted many municipalities to enact bans on these chemicals.

Early blue violet (Viola adunca) is a short, native violet that can add biodiversity to your lawn. © Manitoba Museum

Further, the popularity of polyculture lawns is experiencing a resurgence. Polyculture lawns more closely mimic a natural ecosystem by including both grasses (ideally, low growing native species like Blue Grama a.k.a. Bouteloua gracilis) and low growing, broad-leaved plants, such as clover (e.g. Trifolium), native violets (e.g. Early Blue Violet a.k.a. Viola adunca), pussytoes (Antennaria spp.) and yes, maybe even some dandelions. Broad-leaved plants provide pollinators with food, and some species, like legumes, naturally add nitrogen to the soil, reducing the need for fertilizers. In shady areas where grass won’t grow well anyway, ground covers of taller, native plants like Ostrich Fern (Matteucia struthiopteris), Western Canada Violet (Viola canadensis) and Canada Anemone (Anemone canadensis) are great alternatives.

White clover (Trifolium repens) may be considered a weed by many lawn purists, but it was once a staple in lawn seed mixes, as clover raises the nitrogen level. © Wikimedia Commons

Trying to keep your lawn “weed” free is like running on a treadmill: you spend lots of energy but you never get anywhere. Why not embrace the diversity of plant life, and save your money and back-breaking labour for something else?

06/14/22

In Search of New Species

When I tell people I am writing a book that describes all of the plants that grow in Manitoba, they are often incredulous. “Don’t we already know how many plants species there are in Manitoba” they ask. Sadly, the answer is no.

To this day, botanists are still finding plants that they did not know grew in Manitoba, like White Avens (Geum canadense). © Manitoba Museum

New to Science

Believe it or not, botanists documented and collected two flowers that were not believed to grow in the province, for the first time ever in 2021. White Avens (Geum canadense) and Tawny Cottongrass (Eriophorum virgatum) grow in northern Minnesota and western Ontario.  However, they had never been scientifically collected in Manitoba before. These species join 268 other species of vascular plants that have been scientifically collected since the publication of the “Flora of Manitoba” book in 1957.

Further, the Royal Alberta Museum’s moss specialist, Dr. Richard Caners, also recently collected 34 species of moss that had not yet been officially documented in Manitoba. So, on average, nearly five new plant species have been added to our provincial list of flora each year for the last 65 years.

This recently acquired collection of mosses, contains specimens of several species that scientists did not know grew in Manitoba. © Manitoba Museum

Found in House

You don’t even need to do field work to find new species! In the last several years, Museum volunteers discovered several previously unknown species in the Museum’s collection of pressed, dried plants. These preserved plants, called “herbarium specimens”, officially confirm the presence of species in the province. Along with the specimen, data on when and where it was collected are provided.   The Manitoba Museum alone has over 50,000 of these herbarium specimens. What makes them so valuable is that they can be examined by experts without having to travel back to the area where the plant was collected.  Scientists use them to determine the rarity of species, and understand how the climate has changed over time, among other things.

This specimen, collected in 1954, was recently determined to be a newly described species, Hickey’s Club-moss (Lycopodium hickeyi). © Manitoba Museum 000004

One of my jobs as Curator is to make sure that all our plants are identified correctly.  This requires studying the  most up-to-date scientific research. While examining specimens of Yellow Evening-primrose (Oenothera biennis), my volunteer and I determined that two specimens were, in fact, a species that was not confirmed to be in Manitoba until very recently: Oakes’ Evening-primrose (O. oakesiana).

Evening-primrose (Oenothera) species are hard to tell apart, even for professional botanists. © Manitoba Museum

Why is Manitoba a Botanical Black Hole?

So why are scientists still finding new plants in Manitoba? Part of the reason is that scientific field collecting is poorly funded. There is a widespread perception that Canada is well-explored biologically, and that there is nothing unusual left to find here. So, such expeditions are typically deemed unimportant and not funded. Another reason is that Manitoba has relatively few roads in the northern ¾’s of the province. This makes it very difficult, and expensive, for scientists to visit pristine areas where rare plants may grow.

Areas near Manitoba’s borders, like Whiteshell Provincial Park, often contain plant species at the very edges of their ranges. © Manitoba Museum

Indigenous Contributions

When I say that a plant species is “new” to the province, what I mean is that no scientist had collected, preserved and stored a sample of that species in a registered herbarium.  This does not mean, however, that no one has ever seen the plant. Someone may have seen it, but not realized that it was anything unusual.

A new species of water-lily (Nymphaea loriana) was located and documented thanks to Indigenous guides from Cross Lake First Nation. © Manitoba Museum

As the stewards of large tracts of undisturbed land, Manitoba’s Indigenous peoples are likely aware of the presence of plant species that professional botanists do not know much about. The Manitoba Museum is beginning to work with Indigenous peoples to incorporate their knowledge on the distribution and rarity of the province’s plants into our database.

05/20/22

The Plants that Ruled When Dinosaurs Did

When most people think of plants, they typically picture flowers: cherry trees in bloom, colourful tulips and exotic-looking orchids. This is because 90% of all living plant species are flowering plants (i.e., angiosperms). But when dinosaurs first evolved 225 million years ago (mya), flowers were nowhere to be found.

Tree ferns, like this one at the Montreal Botanical Garden, were common when dinosaurs still existed. © Manitoba Museum

First Plants
The first land plants did not produce seeds; instead, they reproduced using spores. Like amphibians, they needed water for reproduction, which restricted them to habitats that were moist. These spore-producing plants included mosses, liverworts, club mosses, horsetails, ferns and several, completely extinct plant groups called Rhyniophytes and Zosterophylls. When the first dinosaurs evolved in the Triassic Period (252-201 mya), spore-producing plants, like tree ferns and human-sized quillworts (e.g. Pleuromeia), were common (Palmer et al. 2009). Although these sorts of plants still exist today, their ancestors looked much different than the ones we are familiar with.

The tiny Prickly Tree Club-moss (Lycopodium dendroideum), which lives on Manitoba’s forest floors, is one of the few surviving club-moss species. © Manitoba Museum

Ancient Seeds
Seed plants evolved in the Late Devonian (416-359 mya), eventually becoming the dominant vegetation by the Early Cretaceous (145-100 mya). A seed consists of a plant embryo, a source of food, and a protective coat. This adaptation helped seed plants, like conifers, gingkos and cycads, out-compete the spore-producing plants, particularly in drier habitats.

Modern Maidenhair trees (Ginkgo biloba) are considered “living fossils” because they look almost exactly like Jurassic fossils of ginkgos. From Wikimedia Commons.

First Flowers
Flowering plants similar to modern magnolias, dogwoods, and oaks, appeared rather abruptly in the fossil record, about 90 mya (Late Cretaceous). Decades of searching by palaeobotanists for the first flowers has finally borne fruit (pardon the pun). The most recent evidence of an undisputed flowering plant is a fossil named Florigerminis jurassica (Cui et al., 2021). The discovery of this fossilized flower bud and fruit, indicates that flowering plants evolved nearly 75 million years earlier than originally thought, in the Jurassic Period 164 mya (Cui et al., 2021).

Dinosaurs would have eaten cycads, plants that produce cones in the very centre of their trunk. This specimen was at the Montreal Botanical Garden. © Manitoba Museum

Floral Rarity
Part of the reason why flower fossils are so rare is because these structures are very delicate. Flowers likely decompose long before they can fossilize. In fact, some species that palaeontologists think were cone-bearing, may have actually borne flowers, since we only have fossils of their leaves. Another reason flowers did not often fossilize, is that Late Jurassic and Early Cretaceous flowering plants may have grown in relatively dry habitats, where fossilization rarely occurs.

Most plant fossils consist of leaves or wood; flowers rarely fossilize. © Manitoba Museum B-254

Changing Ecosystems
It wasn’t just the animal world that changed when that giant asteroid hit the earth 66 mya; it was the plant world, too. In North America, about 50% of the plant species (mainly the slower-growing, cone-bearing plants) went extinct at the end of the Cretaceous period (Condamine et al. 2020). Afterwards, the evolution of flowering plants was rapid, thanks in part to coevolution with pollinating insects like bees (Benton et al. 2022). With their quick growth, drought tolerance, and long-lived seeds, flowering plants were better able to colonize the devastated earth than cone-and spore-bearing species (Benton et al. 2022, Condamine et al. 2022). Thus, the evolution of flowering plants parallels that of mammals.

Many modern flowering plants, such as Early Yellow Locoweed (Oxytropis campestris), coevolved with pollinating insects, such as bumblebees (Bombus). © Manitoba Museum

So, when you visit the “Ultimate Dinosaurs” exhibit at the Manitoba Museum this summer, remember to look closely at the murals behind the dinos. They accurately portray the kinds of plants that supported those ancient creatures so long ago.

Mural art from the Ultimate Dinosaurs exhibit showing ancient vegetation communities. © Ultimate Dinosaurs Presented by Science Museum of Minnesota. Created and Produced by the Royal Ontario Museum. Mural Artist: Julius Csotoyi

References
Benton, M.J., Wilf, P. and Sauquet, H., 2022. The Angiosperm Terrestrial Revolution and the origins of modern biodiversity. New Phytologist, 233(5), pp.2017-2035.

Condamine, F.L., Silvestro, D., Koppelhus, E.B. and Antonelli, A., 2020. The rise of angiosperms pushed conifers to decline during global cooling. Proceedings of the National Academy of Sciences, 117(46), pp. 28867-28875.

Cui, D.F., Hou, Y., Yin, P. and Wang, X., 2021. A Jurassic flower bud from the Jurassic of China. Geological Society, London, Special Publications, 521.

Palmer, D., Lamb, S., Gavira Guerrero, A. and Frances, P. 2009. Prehistoric life: the definitive visual history of life on earth. New York, N.Y., DK Pub.

04/12/22

A fruit in vegetable’s clothing

Like many of you, I am eagerly awaiting spring so that I can start planting my vegetable garden. There’s nothing better than eating bruschetta with freshly harvested vine-ripened tomatoes (Solanum lycopersicum) and steamed green beans (Phaseolus sp.) with fried cream (see recipes at the end). My mouth drools just thinking about it! But the funny thing about tomatoes and green beans is that they are not actually vegetables: they are fruits masquerading as vegetables.

When you eat fresh green beans, you are eating the fruit (outer pod) and the immature seeds inside. From Wikimedia Commons.

In fact, there are many other things we think of as vegetables that are actually fruits: avocados (Persea americana), cucumber (Cucumis sativus), eggplant (Solanum melongena), okra (Abelmoschus esculentus), olives (Olea europaea), peppers (Capsicum spp.), snow peas (Pisum sativum), squashes including pumpkin (Cucurbita spp.), tomatillos (Physalis spp.) and zucchini (Cucurbita pepo). We tend to define fruits as plant parts that are sweet and vegetables as plant parts that are not sweet. However, botanically, a fruit is a ripened ovary that contains seeds inside it, so all of the aforementioned plants meet the definition of a “fruit”, even though we rarely eat them the way we eat fruit (in a pie with ice cream!). For this reason, some people call them “vegetable fruits”.

Although it is not sweet, avocado is still considered a fruit because of the seed inside. From Wikimedia Commons.

Complicating things further is the fact that the fleshy parts of some “fruits”, like apples (Malus domesticus), pears (Pyrus spp.) and strawberries (Fragaria spp.), are not actually ripened ovaries at all, but greatly enlarged fleshy petals, or upper flower stalks (see Why a Strawberry is not a Fruit for a more thorough explanation).

The apple “fruit” is actually just the core; the fleshy part we eat is formed from petal tissues. From Wikimedia Commons.

“Aha” you might be thinking, what about bananas (Musa spp.)?  They don’t have seeds. You may have noticed though, that there are little black specks inside bananas; those are tiny ovules (unfertilized seeds) that never ripened  because the plants are sterile. Since people don’t usually like spitting out seeds, plant breeders have found ways to produce sterile, seedless varieties (often with an odd number of chromosomes) of certain plants such as citrus fruits, watermelons (Citrullus lanatus) and bananas.

Seeds inside a wild, fertile banana. From Wikimedia Commons.

There are actually four different kinds of vegetables, which vary according to the part of the plant you are actually eating: roots, stems, leaves, or inflorescences. Root vegetables are either fairly slender taproots (e.g. carrots or Daucus carota), or swollen, tuberous roots (e.g. sweet potato or Ipomoea batatas).  Roots store starch that the plant can use the following year to grow new leaves.

Some of the vegetables we eat consist of stems (e.g. corms, tubers and rhizomes) or leaves (e.g. bulbs) that grow underground.  Like roots, these structures are fleshy and store starch.  However, corms grow upright and rhizomes grow horizontally. Tubers, on the other hand, can grow in any direction.  Tubers also possess tiny “eyes” all over it that represent leaf buds. For this reason, you can plant a single tuber (or just part of it as long as there is an “eye” on it), and it will grow into a whole new plant.

The non-green parts of bulbs, like onions (Allium cepa), are actually special, fleshy leaves that store starch. Some vegetables, like broccoli (Brassica oleracea), actually consist of upper stems and unopened flowers, known as inflorescences. See the table below to find out what your favorite vegetables actually are.

Table 1. Plant parts that vegetables represent.

Main plant part Category Examples
Root Beets, burdock, carrot, cassava, celeriac, daikon, horseradish, parsnip, radish, rutabaga, sugar beet, sweet potato (Ipomoea), turnip
Stem (above ground) Stalk Asparagus, bamboo shoots, celery, cinnamon, fiddleheads, heart of palm, kohlrabi, rhubarb
Stem (below ground) Corm Taro, water chestnut
Rhizome Galagal, ginger, lotus, turmeric, wasabi
Tuber Jicama, oca, potato, sunchokes, yam (Dioscorea)
Leaf (below ground) Bulbs Garlic, leeks, onion, shallots
Leaf (above ground) Greens Arugula, bok choi, Brussel sprouts, cabbage, Chinese mustard, dandelion, endive, goosefoot, herbs (e.g. basil, oregano, rosemary), kale, lettuce, mustard greens, nettle, rocket, spinach, sorrel, Swiss chard, watercress
Inflorescences Artichoke, broccoli, capers (flower buds), cauliflower, rapini

Seed potatoes are tubers that can be planted to grow new plants. From Wikimedia Commons

To finish off, here are two of my favorite “vegetable fruit” recipes. Unfortunately, you’ll just have to wait a few more months to try them.

Bruschetta
Coarsely chop however many fresh tomatoes you want to eat, and put in a bowl. Mix in coarsely chopped onions and some sliced fresh basil. Pour in enough olive oil and balsamic vinegar to generously coat. Season with salt and pepper and toss. Let sit for 15 minutes. Heap onto garlic toast and savour the flavour of summer!

Beans with Fried Cream
Steam fresh yellow or green wax beans until tender. Meanwhile, finely chop some onion and sauté with butter till golden over medium heat. Add cream to pan and cook, stirring until thickened. Add paprika, salt and pepper to taste. Pour over cooked beans and toss. Bon appétit!

01/28/22

The Weird World of Plant Sex

On the surface, plant sex seems pretty simple. Birds and bees transfer pollen from one flower to another and voila: seeds are produced. But, like most things in life, plant reproduction is much more complicated than initially meets the eye.

Some plant species, like Manitoba Maple (Acer negundo) have separate male and female trees. This tree is female, and has produced winged seeds. Image: © Manitoba Museum

FINDING A MATE

For starters, plants are not like mammals when it comes to gender. Only about 5-6% of all flowering plant species are dioecious, that is, having separate “males” (i.e. producing only sperm-containing pollen in stamens) and “females” (i.e. producing only eggs in pistils). The most familiar dioecious plants to most people are Manitoba Maples (Acer negundo), willows (Salix spp.) and marijuana (Cannabis sativa). However, the vast majority of plant species are monoecious, producing both sperm AND eggs in a single plant.  This strategy makes sense for organisms that can’t move around to find a mate. When you make both sperm and eggs, your possible number of romantic encounters doubles. Most of the common garden flowers that we love, such as lilies, roses, tulips and orchids, are monoecious.

The flowers of Western Red Lily (Lilium philadelphicum) have a single pistil in the center, which contains the eggs, and six sperm-producing stamens surrounding it. Image: © Manitoba Museum

Some species are cosexual, with both stamens and pistils in the same flower (e.g. Western Red Lily (Lilium philadelphicum). Other species produce separate male and female cones or flowers on different parts of the same plant, or at different times of the year. For example, White Spruce (Picea glauca) trees produce male cones at the bottom of the tree and female cones at the top. Alder (Alnus spp.) shrubs typically produce their male flowers first, and then their female flowers afterwards. The separation of pollen- and egg-production in either space or time, helps prevent self-pollination and inbreeding.

The female cones of White Spruce (Picea glauca) are usually near the top of the tree and the male cones near the bottom, to prevent self-fertilization. Image: © Manitoba Museum

However, even plants with separate “males” and “females” may be able to change sex in a pinch. Imagine what would happen if all the plants in a certain area happened to be female. No babies would be made at all! Scientists have described instances of plants switching from making female flowers to male flowers in response to environmental conditions (Freeman et al. 1980). Light levels, soil fertility and temperature are some of the factors known to alter floral sex in certain species (Varga and Kyto viita 2016; Freeman et al. 1980). When resources are scarce or growing conditions poor, making sperm is less energy-intensive than making eggs and seeds. Thus, for example, a dioecious tree may produce male flowers when it is young and short, and female flowers when it is older and taller, as larger trees capture more light.

Four-wing Saltbush (Atriplex canescens) plants have been documented as changing gender after particularly stressful weather events, like cold temperatures and drought (Freeman et al. 1984). Image: © Manitoba Museum, 29685

GOING SOLO

But we have only scratched the surface of plant weirdness. Sometimes, flowers will not receive any pollen.  This means that all the energy invested in egg production will go to waste. In the name of efficiency, some species, like sunflowers (Helianthus spp.), self-pollinate by curling parts of their pistils around their stamens. In other species, a process called agamospermy results in the egg maturing into a seed without being pollinated at all. It’s kind of like a virgin birth, with the offspring being genetically identical to the parent plant.

Other species, often those in cold, alpine or arctic climates, don’t even bother producing seeds; they just make tiny clones of themselves called bulbils.  This is a kind of asexual reproduction. Once the bulbil is large enough, it detaches, perhaps when a stiff breeze is blowing, and grows into a new plant. That would be like growing a tiny version of yourself on the outside of your belly (like a giant pimple). Then one day it would just fall off and become a new person that looks exactly like you. Native plants like Bulb-bearing Water-hemlock (Cicuta bulbifera) and Viviparous Sheep’s Fescue (Festuca viviparoidea), and house plants like Kalanchoe (Kalanchoe spp.) use this technique to reproduce.

Sunflowers (Helianthus annuus) can pollinate their own seeds if they have to, but production is lower and the offspring are not as genetically diverse. Image: © Manitoba Museum

Plants also engage in vegetative reproduction. This is when plant parts, like leaves or stems, that become detached go on to grow roots and become new plants. Many cacti and other succulents, can do this: cactus “pads” (actually swollen stems) that become detached grow into new plants under the right conditions. For humans, this would be like removing a leg, and then having it grow into a clone of yourself. The “parent” would then grow a new leg to replace what was lost, kind of like what the Marvel Cinematic Universe character Deadpool did in the movie sequel (his whole body regrew from his head!).

Cactus pads of Plains Prickly-pear Cactus (Opuntia polyacantha) that become detached can grow into new plants. Image: © Manitoba Museum

Plants have had to evolve some ingenious ways to ensure their reproductive success because they are rooted in one spot. Imagine how much stranger our lives would be if humans reproduced like plants.

References
Freeman, D.C., K.T. Harper, and El L. Charnov. 1980. Sex change in plants: old and new observations and new hypotheses. Oecologia, 47: 222-232.
Freeman, D.C., McArthur, E.D., and K.T. Harper. 1984. The adaptive significance of sexual lability in plants using Atriplex canescens as a principal example. Annals of the Missouri Botanical Garden, 71: 265-277.
S. Varga, M.-M. Kyto viita. 2016. Light availability affects sex lability in a gynodioecious plant. American Journal of Botany, 103: 1928-1936.

11/30/21

Who turned out the light?

With the days growing ever shorter, I find myself thinking about light and how we tend to take for granted the hard work that plants do, harnessing the energy from the sun. Photosynthesis is the beginning of most food chains on earth, the exceptions being bacteria (Archaea) that can obtain energy from inorganic chemicals like sulphur and ammonia. But since we don’t eat bacterial ooze for breakfast, this process remains relatively unimportant to humans. Photosynthesis is what gives us life!

Plants like Bunchberry (Cornus canadensis) engage in photosynthesis, one of the most important chemical reactions on earth. (c)  Manitoba Museum

Photosynthesis is a process where plants, and plant-like aquatic creatures such as phytoplankton, use energy from the sun (photons) to combine water (H2O) with carbon dioxide (CO2) from the air, to make sugar (C6H12O6). Oxygen (O2) is a “waste” product of photosynthesis. This reaction takes place in special green-coloured plant cells called chloroplasts. Plants and phytoplankton use the sugar they make to grow and reproduce themselves.

Animals and fungi are incapable of photosynthesizing; they have to “eat” plants to stay alive. Even meat-eaters (i.e. carnivores) are ultimately dependent on plants for their survival, because they eat animals that eat plants or phytoplankton. Further, the oxygen that plants produce is also required by animals to breathe. Thus, we depend on plants for our very lives.

All animals, including insects like this bumblebee (Bombus sp.) on a sunflower (Helianthus sp.), depend on plants for food. (c) Manitoba Museum

Some northern plants are “evergreen”, which lets them begin photosynthesizing as soon as the ground thaws in spring. In contrast, deciduous plants have to grow a whole new set of leaves before they can begin photosynthesizing again. As there is almost continual sunlight over the summer months in the far north, tundra plants can photosynthesize almost non-stop during this time. They must quickly produce enough sugar over the short summer to stay alive, in a dormant state, over the long, dark winter.

The evergreen Purple Saxifrage (Saxifraga oppositifolia), begins photosynthesizing as soon as it can, even when there is still snow on the ground. (c) Manitoba Museum

One way that plants can increase the amount of light they receive is by slowly moving in response to the direction of the sun (i.e. heliotropism). Like tiny solar ovens, species such as Entire-leaved Mountain Avens (Dryas integrifolia), move their flowers each day so that they continually face the sun. As a result, the flower temperature is several degrees warmer than that of the air. This improves seed production, in part, because pollinating insects are more likely to visit warmer flowers. In other plant species (e.g. sunflowers or Helianthus) it is the leaves that rotate to be perpendicular to the sun, increasing the amount of light for photosynthesis.

The umbrella-shape of the flowers of Entire-leaved Mountain Avens (Dryas integrifolia), concentrates the sun’s rays on the young seeds developing in the center. (c) David Rudkin

Many ancient human societies in the northern hemisphere held religious gatherings or celebrations around the winter solstice (typically Dec. 21 or 22) because even though they knew many cold days were still ahead, the amount of sunlight would begin to increase again. Evergreen plants, like spruces, pines, mistletoes and holly, were sometimes part of these events, because they are the plants that refuse to wither when the light begins to fade.

09/14/21

Hot to Trot: Plant Hunting in a Drought

Doing biological field work always comes with challenges. Since I began working at the Museum in 2003, the summers have been relatively wet. As a result, I’ve had to deal with muddy roads, many, many biting insects thirsty for my blood, and bootfuls of water obtained while exploring flooded wetlands. This year though, the roads were good, the biting insects non-existent, and many wetlands were so dry that I could walk right into the middle of them-no rubber boots required! In contrast, my main concern this year was possibly getting heat stroke!

This wetland near Lac du Bonnet that I visited was almost completely dry.

As part of my research for a new book on Manitoba’s flora, I’ve been trying to track down populations of historically-collected plants (some of which haven’t been collected for over 100 years) to see if they still grow here. Fortunately, this year, all of the sites I needed to visit were close to major bodies of water: Lake of the Woods, Lakes Winnipeg and Manitoba, and Lac du Bonnet. As a result, I was able to go for a quick swim in the nearby body of water to cool off after a long day of hiking. Swimming is especially satisfying when you have been wearing long pants, wool socks and hiking boots in 30°C+ temperatures all day. Field work this year also involved drinking copious amounts of water (which were nearly completely sweated out given that I didn’t have to go to the bathroom all day!), lots of SPF 50 sunscreen, taking breaks under the shade of a tree, and wearing a cooling, water-soaked bandana around my neck.

Dipping my hot feet in the cool lake water at Elk Island Provincial Park felt amazing!

I also got lucky with my field work, finding a new rare plant population and a new plant species for the province. The first rare plant species I discovered was Hairy Bugseed (Corispermum villosum). This species is currently ranked S1 (critically imperilled) in Manitoba because there are only three populations known in the province. I discovered a small population at St. Ambroise Beach Provincial Park on Lake Manitoba. Additionally, the population of this species that occurs out at Lake Winnipeg was found to be more extensive, extending all the way to Elk Island Provincial Park.

A new population of Hairy Bugseed was discovered at St. Ambroise Beach Provincial Park.

Out at Lake of the Woods, there are several plant species that reach the northeastern edge of their range. One is the lovely Small Purple Fringed-orchid (Platanthera psycodes). It was suspected to occur in Manitoba, but no one had actually collected a specimen until 1984. As I had never seen it before, I was thrilled to find and photograph the two plants in flower at the site.

The Small Purple Fringed Orchid was an exciting, and beautiful find!

Not far from the orchid, I saw another plant that I was on the lookout for: White Avens (Geum canadense). Although this species is relatively common in Ontario, Quebec, New Brunswick and Nova Scotia, it has apparently never been collected in Manitoba before. I carefully removed part of the stem only (not the root) to make an herbarium specimen, after verifying that there were more than ten additional plants in the vicinity.

I collected the first ever specimen of White Avens in Manitoba this summer.

Finding these new, rare plant populations made the hot, July temperatures much easier to handle. The specimens collected will be carefully preserved in perpetuity at the Museum to document these plant populations for conservation purposes, and for future researchers to study.

08/18/21

The Importance of Being a Flower

Like many of you, I enjoy walking through my neighbourhood and smelling the sweet fragrances of the summer flowers. Unfortunately, like many things, flowers are ephemeral. When I see a flower, I am always reminded of the Robert Herrick poem urging us to:
“Gather ye rosebuds while ye may,
Old Time is still a-flying;
And this same flower that smiles today,
Tomorrow will be dying.”

A new, temporary exhibit on seeds is in the Museum’s foyer.

(more…)

05/12/21

Travelling Plants of the Prairies

Plants and fungi were challenging organisms to include in our new Prairies Gallery because most of our 50,000+ Museum specimens are preserved in a flattened, dehydrated condition. Not very attractive! Further, because these organisms don’t move the way animals do, people don’t seem to find them interesting. But are they really the passive, immobile creatures that we think they are? Our new exhibit case called Travelling Plants and Flying Fungi, attempts to dispel this notion.

Most Museum specimens are dried and flattened, like this Stiff Goldenrod (Solidago rigida) plant.

The fact of the matter is, plants and fungi need to be able to move, otherwise they would never have colonized land! However, it is not the adults that do the actual moving; it is their gametes (pollen) and offspring (seeds). Before a plant can make seeds, it has to have its eggs fertilized by pollen grains from another plant. Since a plant can’t just get up and walk to another plant to give it some pollen, they have to use wind or animals, called pollinators, as couriers. To depict this process, the new Museum case includes intricate 3-D models of a wind-pollinated grass and four animal-pollinated flowers, as well as their pollinators, instead of flattened plants.

Before the final graphics were chosen, the layout of the case needed to be tested.

The plant models were created by the Museum’s talented Diorama & Collections Technician. Two of the models are real plants that were “mummified”, and then painted to look alive. The other three are entirely artificial. To make them, a plant was collected, and then molds made of the parts. These molds were used to create fake leaves, stems, flowers and fruits, which were then assembled together and painted.

The Golden Alexanders (Zizia aurea) model has two pollinators on it: a beetle and a butterfly.

Once a plant is pollinated, seeds, protected inside fruits, develop. Seeds also need to disperse, and, once again, wind and animals are the couriers. To illustrate the different methods of dispersal, various seeds and fruits from the Museum’s collection were selected for display.

Inset cases display various kinds of fruits and seeds. These species have hooked burs that catch onto animal fur.

Some plants, fungi and lichens do not produce multi-celled seeds; they produce tiny, single-celled structures called spores. Since they are so small, they typically disperse very well in the wind. Specimens of several common prairie spore-producers, including fungi and club-moss, are displayed in between the plant models.

Puffball fungi (Calvatia spp.) were collected, and quickly dehydrated, for this new display case.

Manitoba prairies have many fascinating plants, fungi and lichens in them. How they survive and reproduce is now one of the stories we tell in the Museum. My only regret is that we couldn’t include more species in the gallery. Hopefully, this new case will inspire our visitors to spend more time paying attention to, and appreciating, the plants in our wild prairies.

Dr. Diana Bizecki Robson

Curator of Botany

See Full Biography

Dr. Bizecki Robson obtained a Master’s Degree in Plant Ecology at the University of Saskatchewan studying the rare plants of the mixed grass prairies. After a few years of working as an environmental consultant and sessional lecturer, she got her Ph.D. in Soil Science from the same University, this time focusing on phytoremediation of hydrocarbon-contaminated soil using native and naturalized plants. Diana joined The Manitoba Museum team in 2003.