Archives For botany

I scratch my head and wipe the sweat from my brow. One of my summer interns found a little plant, under a bunch of big plants, and we thought for a second it might be the same as the big plants, but it is definitely different. It’s our first field day. We don’t know what this plant is called, and it’s a hot and humid summer day in Chicago, and we have been searching through our identification guidebooks for what seems like forever. “Is it this one?” we ask each other, pointing to pictures in the book where the leaves kinda sorta look like our little plant. Finally, we flip through the book one last time, and it seems to open all on its own to the right place. It’s called water horehound (Lycopus americanus). We cheer! Now that we know this little plant’s name, we start to see it everywhere.

PHOTO: Poring over a specimen in the field.

Poring over a specimen in the field

I’ve been working all summer with a fresh-faced team of undergraduate interns to quantify plant community biodiversity (i.e. identify and count plants) in restored prairies around Chicago. Some of our sites have been right by the lake, some have been in community parks, some in forest preserves, and one in what seemed to be a drainage ditch. So far, we have identified more than 200 plant species.

Biodiversity is all around us. And I’m not just talking about in the tropical rainforest or a coral reef, though there are many species there, too. Even in the temperate zone, even in a park, and probably even in your backyard, there are many species. A species is defined as a group of organisms that can breed with one another. While most people would feel comfortable declaring that an elephant is different from a carp, an oak tree, or a shiitake, there are often much more subtle distinctions that can signify that organisms belong to different species. To humans trying to identify plants, the distinction between two species could be as minute as whether the leaf hairs are hooked or straight. Seeing species is hard but worthwhile. It will help you develop keen observation skills, and (I hope!) an appreciation of the world around you.

PHOTO: Dodecatheon meadia.

Shooting star (Dodecatheon meadia) is a distinctive early flowering species of the prairie. Photo by Jessica Riebkes

Before we can identify what a species is, we first have to determine that it is something different from the other surrounding plants. We tend to look at plants as a bunch of green stuff, not always recognizing the diversity present even in seemingly mundane habitats. We call this phenomenon “plant blindness,” the tendency to see plants as background, and not as unique organisms. My Ph.D. advisor said I should call our inability to recognize differences between species, “species blindness” (The only other reference I could find for species blindness was in Rutgers University Professor Lena Struwe’s bioblitz project).

Recognizing differences among species is only the first hurdle. Then, you have to identify them. The identification can be confounded in many ways, like the issue of timing. Some species may be distinctive at maturity but can remain a mystery at other times. Take rattlesnake master (Eryngium yuccifolium). There is no mistaking the master when it’s flowering. The flowers are small, green and white, but are contained within a spiky ball of a flowering head. The leaves are thick, pointy, and spear-like, prickles sticking out all along the edges. But when the mighty rattlesnake master pokes out of the ground in the spring, you would definitely mistake it for a grass; there are no flowers, no spiky balls, no spears. The only way to know it isn’t a grass is to observe the sparse, puny prickles just starting out.

PHOTO: Rattlesnake master (Eryngium yuccifolium) with a co-occuring species.

The distinctive rattlesnake master (Eryngium yuccifolium with co-occuring species. How many can you spot?

And while we’re at it, let’s talk about grass. (No, no I am not talking about marijuana.) Botanist Chris Martine already addressed that in his essay, “I am a botanist, and no, I don’t grow marijuana.”) I just mean grass, the stringy green stuff that grows out of the ground. This demonstrates another hurdle to combating species blindness: the sheer number of species out there. Guess how many species of grass there are. Go ahead, guess. The Royal Botanic Gardens, Kew keeps a database of grasses called, of course, GrassBase. Currently, GrassBase includes 11,313 different species of grass. Grass is actually a plant family, containing many different species (please see this amazing rap if you need a refresher on biological classification). As you can figure out by exploring an overgrown park, an abandoned field, or my favorite place to study grass, a prairie, there are grasses that are incredibly distinctive. Some have seedheads that smell like popcorn! Sometimes, though, the grass isn’t blooming (grasses are flowering plants, by the way), and you end up pulling back leaf after leaf trying to find a ligule to help with the identification. A ligule is what’s found where a grass leaf blade meets the stem. The ligule can be rigid or floppy, membranous, or hairy, or totally absent. Once you know that the ligule exists, you might try to find it on any and all grasses you pass (I do!).

Once you’ve found a distinct species, how do you figure out its name? We budding botanists have a few tricks. We search through field guides so many times that we memorize the pages for certain families. We spend a lot of time looking at the glossary of our field guides, trying to remember the meaning of botanical terms like panicle, petiole, connate, cordate, corolla, and cyme. We use multiple senses. We are known to crush leaves and breathe deep, searching for the piney smell of a goldenrod, the freshness of a mountain mint, or the musk of bee balm. We are almost obsessive about our rubbing of leaves to distinguish new textures. And we hunt for tiny clues (often with a hand lens) like a line of hairs down a stem or a gland at the base of a hair on the edge of a leaf blade. We value the time we get to spend in the field or the lab with expert botanists that put our identification skills to shame. And when all else fails, we post to Twitter or Facebook botany groups and someone always knows.

PHOTO: Becky Barak in the field.

The best part of the job—doing research in the field!

I’m asking you to combat species blindness by working hard to notice species. Dig a little deeper, look a little closer. If you’re out with children, challenge them to find as many different species as they can. At first glance, it may seem like everything is the same, but with careful observation, the species will begin to show themselves. Look at all parts of the plant. Flowers sometimes get all the love, but stems and leaves and fruits and seeds can hold the keys to identification. Plants are a good place to start because they are known to stay in one place, but the same patterns apply to all living things. Biological diversity is out there; you just need to know how to look.


©2015 Chicago Botanic Garden and my.chicagobotanic.org

Pollen 101

Karen Z. —  September 10, 2015 — 1 Comment

Did you have a flashback to science class when you saw Spike, the titan arum? I sure did.

PHOTO: Tim Pollak and Dr. Shannon Still point out plant parts of the titan arum to the gathered crowd of visitors.

With Spike’s frilly spathe removed, Tim Pollak and Dr. Shannon Still had a rare opportunity to show the crowd the titan arum’s beautiful and astonishing inner plant parts.

At my not-really-science-minded high school, botany (the study of plants) was taught as a subsection of biology (the study of all life) class. During the botany rotation, we learned a bit about plant names and plant parts, sprouted a few seeds, and dissected a plant. That was about it for my formal plant-science education.

PHOTO: A young girl sniffs the titan arum's removed spathe.

Hands-on plant science at the Garden: a young visitor gets a whiff of Spike’s removed spathe, looking for that telltale stench.

Flash forward a couple of decades and, despite now being an avid gardener, I found myself struggling to keep up with the scientists who were looking deep into Spike’s structures and processes. By the time Dr. Shannon Still and floriculturist Tim Pollak removed the spathe (the frilly bract that never opened) from Spike’s spadix (the flower tower that grew to 6 feet tall), I’d had to learn all about the titan arum’s morphology (see below) and crack open books and laptops to review the basics about male and female flowers.

And then they started talking pollen.

Flashback: What is pollen?

PHOTO: Closeup of pollen emerging from male Amorphophallus titanum flowers.

Tiny squiggles of pollen emerge from the male flowers about three days after Spike’s spathe was removed.

Think of a grain of pollen as a tiny packet of one plant’s genetic material that needs to meet up with another flower’s female genetic material. Technically, pollen is a haploid or gamete, the cell that carries the male half of the plant’s chromosomes.

The covering of a pollen grain is directly related to how the pollen travels to the next flower. That’s why wind-pollinated plants like sweet corn or oak trees have pollen as dry and fine as dust (indeed, the word “pollen” derives from the Latin for fine flour or dust). Orchids have developed waxy balls of pollen (pollinia) that stick to the heads and bodies of the many insects, hummingbirds, and mammals they use as pollinators. And, notoriously, the pollen of ragweed is a tiny spike—the better to hold on to moist spots like the inside of human nasal passages, where the grains never germinate, but cause all sorts of sneezing and snuffling.

Honeybee-pollinated plants (like many fruits, nuts, and vegetables) have evolved along with the bees themselves, offering up both nectar and pollen as food in exchange for the movement of pollen from plant to plant.

Flashback: Why are insects pollinators?

In a word, efficiency. Plants that rely on the wind are at the mercy of the wind: much of the pollen is wasted, as it never lands anywhere near a female flower’s stigma. Ditto for plants that rely on water. Insects are much more reliable, traveling directly from one flower to another, greatly increasing the chance of pollination. Bees are especially reliable, as they prefer to work an entire plant or crop of the same flower rather than skipping from one kind of flower to another. (That’s why attentive beekeepers can get a harvest of “pure” clover or linden blossom honey, rather than a wildflower mix.)

In nature, Spike’s pollinators are carrion beetles and dung flies—insects that would be attracted by the titan arum’s rotten smell and nighttime bloom.

Flashback: How does pollen work?

PHOTO: A single female flower from titan arum Spike lies in Dr. Shannon Still's hand.

Dr. Shannon Still shows the crowd gathered around Spike one of the titan arum’s female flowers .

When a grain of pollen lands in the right place—the tip of the female flower’s reproductive structure, called the stigma—the pollen grain chemically tests the landing ground via proteins that signal genetic compatibility…or not. If deemed to be a good place to germinate, the pollen grain sends a rootlike sprout down into the style (the tube with the stigma on top), eventually reaching all the way down inside the ovary and ovule…where the male chromosomes and female chromosomes meet for fertilization and seed development.

Flash forward: What’s next for Spike?

Spike’s pollen never got the chance to hitch a ride on a carrion beetle’s back to the next titan arum in the rainforest. That’s why “Titan Tim” Pollak collected the pollen when it developed a couple of days after Spike’s operation.

Pollak says that they didn’t collect much of the bright yellow, talc-like powder—just a few test tubes’ worth (further proof that Spike ran out of energy). The pollen will be mixed with powdered milk—yes, powdered milk—in order to absorb moisture and separate the grains. Next, it will be frozen at minus 20 degrees Fahrenheit and stored in the freezer at the Garden’s seed bank.

PHOTO: As the spadix collapses from age, horticulturist Tim Pollak harvests the pollen from Spike's male flowers.

As the spadix collapses from age, horticulturist Tim Pollak harvests the pollen from Spike’s male flowers.

Spike’s pollen could then be shared with other botanical gardens or arboreta that would like to pollinate their blooming titan arums. The American Public Gardens Association has a listserve that shares notice of pollen needed or available; the Chicago Botanic Garden is a contributing member. By sharing Spike’s pollen, the hope is to increase diversity among the rare flowers blooming outside of Sumatra, the titan’s native habitat.

Pollen means that Spike lives on! Can’t wait for the next titan arum to bloom (we have seven more besides Spike in our production area)…and for the next plant flashback.

So you want to be a plant scientist?

PHOTO: Amorphophallus titanum pollen in a test tube.

An Amorphophallus titanum pollen sample is ready to be stored for future pollination.

The science of botany runs deep; at our Daniel F. and Ada L. Rice Plant Conservation Science Center, you can see scientists in many of the fields below in action. Got a STEM-minded kid? Perhaps he or she would like to study this list, which was compiled by Boyce Tankersley, director of living plant documentation, in response to the question, “What is the study of flowers called?”

  • Botany is the study of plants.
  • Arboriculture is the study of trees.
  • BioInformatics is the art and science of recording biological information.
  • Cellular biology is the study of cell constituents.
  • Floristics refers to the geographic distribution of plants.
  • Genetics is the study of gene interactions.
  • Horticulture is the art and science of growing plants.
  • Nomenclature is the naming of plants.
  • Paleobotany searches out and examines plant fossils.
  • Plant breeding does what it says.
  • Plant morphology is the study of plant structures.
  • Plant pathology studies plant pathogens and plant interactions.
  • Plant physiology is the study of plant functions such as photosynthesis.
  • Palynology studies both living and fossilized pollen and spores.
  • Taxonomy studies the relationship of one plant to other plants.

©2015 Chicago Botanic Garden and my.chicagobotanic.org

Dragon Mouth Orchid

 

Orchids are reaching their peak in The Greenhouses. The dragon mouth orchid is native from Guatemala to Panama, where the subspecies rosea is found. This dragon mouth orchid (Encyclia cordigera var. rosea) is in the Tropical Greenhouse, lower level, east epiphyte tree. The flower spikes can produce flowers for up to three months, and each of the flowers smells like chocolate. This species requires very bright light whether grown in greenhouses, on a windowsill, or under artificial lights. During the summer growing season it prefers a moist, humid growing environment, but in the winter the watering should be reduced and diurnal — the difference between night and day low temperatures — with temperature fluctuations of 10 degrees to initiate flower production. Learn more about what’s in bloom here.  http://www.chicagobotanic.org/inbloom/highlight_archive/highlight_022812.php

This summer, 40 middle school students and 20 high school students were immersed in the world of science at the Chicago Botanic Garden. They learned from classroom experiences, working side-by-side with Garden experts, and from being surrounded in nature for the summer. The Garden is committed to preparing the next generation for careers in science through Science First and College First and the science careers continuum. Visit http://www.chicagobotanic.org/ctl/sciencefirst for more information on Science First and also http://www.chicagobotanic.org/ctl/collegefirst for more information on College First.

Chicago Botanic Garden camp instructor Aimee Frank discusses the fun and adventures kids experience during Spring Break Camp and Camp CBG. During Spring Break Camp (March 29-April 2) children ages 5-8 discover bulbs, look for birds and other wildlife, and learn about all aspects of nature at the Chicago Botanic Garden. Starting in mid-June, children can attend Camp CBG which provides exciting outdoor learning opportunities for kids ages 2-15.