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. 

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. 

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. 

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). 

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. 

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. 

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. 

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.

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.

Above: 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 during summer 2022, 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.

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.

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”.

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.

“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.

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.

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.

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

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!

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!

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; left, below), 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.

Some species are cosexual, with both stamens and pistils in the same flower (e.g. the Western Red Lily, Lilium philadelphicum; centre, above). 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. Right, above) 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.

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.

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!).

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!).

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.