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Most plants hate saltwater. Pour saltwater on your houseplants and, a little while later, you’ll have some wilty plants. But mangroves can grow—and thrive—in saltwater.

You may have seen mangroves if you’ve been to the Florida Everglades or gone to an island in the Caribbean. Mangroves are trees that live in tropical, coastal zones and have special adaptations for life in saltwater. One of these adaptations is in how they reproduce: mangroves don’t make seeds. Instead, they make living, buoyant embryos called propagules (prop-a-gyule).

Mangrove propagules come in different shapes and sizes. Each species has its own unique propagule.

Mangroves produce a huge number of propagules the same way an oak would make hundreds of acorns.

Mangroves produce a huge number of propagules the same way an oak would make hundreds of acorns.

These relatively small propagules could become giant red mangrove trees.

These relatively small propagules could become giant red mangrove trees.

Black mangrove propagules on a branch; their outer coating will dissolve on their journey downstream.

Black mangrove propagules on a branch; their outer coating will dissolve on their journey downstream.

Propagules come in different shapes and sizes. These are from a tea mangrove (Pelliciera rhizophorae) tree.

Propagules come in different shapes and sizes. These are from a tea mangrove (Pelliciera rhizophorae) tree.

Normally, trees reproduce with seeds. You’ve probably seen the whirlybirds of maples and acorns of oaks. These seeds can go dormant. They are basically “asleep” or hibernate until something—water, temperature, or physical damage—wakes them up, allowing them to start growing months or years after they are produced.

Here I am with a couple of mangrove specimens. These roots are in water at high tide, but exposed at low tide.

Here I am with a couple of mangrove specimens. These roots are in water at high tide, but exposed at low tide.

Propagules, on the other hand, don’t have that luxury—they fall off their parent tree, ready to start rooting and growing a new tree. Nature has provided an amazing way for the mangrove seeds to move away from the parent tree: they float.

As the propagules float through the water, they shed their outermost layer and immediately start growing roots. The clock starts ticking as soon the propagules fall—if they don’t find a suitable place to start growing within a certain amount of time, they die. If a mangrove propagule ends its journey at a location that’s suitable for growth, the already-rooting propagule will send up its first set of leaves—cotyledons.

Ocean currents can take propagules thousands of miles away from where they started. A mangrove’s parent tree might be around the corner or around the continent.


Dr. Emily DangremondDr. Emily Dangremond is a postdoctoral researcher at the Smithsonian Environmental Research Center and a visiting scientist at the Chicago Botanic Garden. She is currently studying the ecological and evolutionary consequences of mangroves responding to climate change at their northernmost limit in Florida.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

When buckthorn moves in to the ecosystem, it dominates.

Imagine a friend invites you to a dinner party, promising a delicious spread of food and libations. You arrive, excited and hungry, only to find nothing but raw kale, brought by an uninvited guest. Regardless of your feelings about kale, this would be pretty underwhelming. The other guests are obviously disappointed about the monotonous spread. Most people leave, and because most people aren’t eating the kale, the kale continues to dominate the party. Even if someone brought in better foods that more people enjoy, there is no room on the tables. The kale is everywhere!

PHOTO: Buckthorn (Rhamnus cathartica).

Common buckthorn (Rhamnus cathartica)

While not a perfect analogy, this anecdote relays the reasons why buckthorn invasion is detrimental to forest ecosystems. The dinner guests are like the other plants and animals that usually live in the woods. They have certain dietary needs, and if those needs cannot be met, they will have to leave and find another place to live. The more one species dominates (kale, or in many local forests, buckthorn) the fewer species can live there, leading to the ecological equivalent of a party that ends at 8:30, just as everyone was arriving. While it may be true that one person at the party really likes kale, it’s hardly fair for the preferences of that person to supersede everyone else’s needs. In the case of buckthorn, many have opposed its removal because that denies robins a berry that they enjoy. However, keeping the buckthorn (which doesn’t belong there in the first place) is like keeping all of the kale on the tables and not allowing for other foods to be served just for that one person. Even more frustrating, the person that likes kale has plenty of other dietary options. Kale isn’t even their favorite food!

PHOTO: The McDonald woods shows healthy filtered sunlight and native plant understory growth after buckthorn removal.

The McDonald woods shows healthy filtered sunlight and native plant understory growth after buckthorn removal.

To many people, the idea of cutting down trees to help forests grow stronger is counterintuitive. But buckthorn is no ordinary tree. It is an invasive species, meaning that it doesn’t belong in Chicago area forests, and it steals resources from the plants that are supposed to live here. So remember, when you hear people talking about cutting down buckthorn, they are actually doing it to make the habitat healthier and more inclusive in the long term. They are working to replace the kale at the party with better food and drinks, ensuring that all the guests that were invited can have a good time, staying up until sunrise.

Read more about our ongoing buckthorn battle, and see the difference removal makes in restoring an ecosystem.


Bob Sherman

Bob Sherman is an undergraduate studying environmental science at Northwestern University. His research interests include prairie restoration and how abiotic factors impact prairie and forest ecosystems. He hopes that his research will have a positive impact on ecosystem restoration and management.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Everything old is new again, especially when you integrate antiques into a twenty-first century home.

Here are some style-savvy tips from two high-profile interior designers, both presenting lectures at the Antiques, Garden & Design Show, April 15 to 17, at the Chicago Botanic Garden.

PHOTO: Martyn Lawrence Bullard.

Martyn Lawrence Bullard

Mixing it up: “Today it’s not really about doing interiors that are filled with one particular period or style,” says Los Angeles-based interior designer Martyn Lawrence Bullard, author of Live, Love & Decorate and the upcoming Design & Decoration (Rizzoli, due in April). “It’s really about learning to be eclectic and how to edit and how to mix and match.”

Balance equals harmony: “Editing is one of the most important elements in creating harmonious interiors,” says New York-based interior designer Timothy Whealon, author of In Pursuit of Beauty (Rizzoli). “The trick is mixing pieces from different periods and countries, juxtaposing textures, i.e., the time-worn against a crisp lacquer, without drawing attention to any particular element.”

PHOTO: Timothy Whealon.

Timothy Whealon

Follow your heart: “When I’m looking for antiques with a client, I’m looking for them to respond to it on an emotional level,” Whealon says. “If it speaks to you, buy it.…If you love it, usually you can find a place to work it in.” Bullard agrees: “The great find is actually just something that you love,” he says. “There should never be a monetary value on things. If you love it, then it is worth a fortune.”

Sensibility of scale: Bullard says that “the most important thing for interiors is scale.…You need to know the scale and size you want and where you are going to put (something).” Measure the spaces you want to fill, as well as the doorways these items need to pass through, ahead of time. A tape measure will come in handy at the Show, too.

Seeing the light: To create a seamless continuum from indoors to outdoors, Whealon writes in his book, “I always start a project by looking out the windows, which more often than not informs my design decisions for the interiors.”

PHOTO: Bold yellow interior design by Martyn Lawrence Bullard.

Bold yellow interior design by Martyn Lawrence Bullard. Photo by Tim Street Porter.

Color your world …“People shouldn’t be afraid of color,” Bullard says. “I think one of the first rules of color is to choose one you look good in.…If you look good wearing it, think how great you’ll look surrounded by it. It really works.”

But don’t forget white: “I like color that gradually reveals itself,” Whealon writes, “and no color has the capacity to do that quite like complex whites.”

PHOTO: Interior design by Timothy Whealon.

Interior design by Timothy Whealon. Photo by William Waldron.

Comfort is king: “The biggest trend in interiors is really comfort,” Bullard says. “People really want to be able to use everything, to be able to sit on everything….The idea of really precious things that you don’t really use is so outdated now.”

Bullard presents “Design and Decoration” at 11 a.m. April 15; Timothy Whealon presents “Classicism Revisited: Mixing Art & Antiques in 21st Century Interiors” at 1 p.m. April 15. Joint lecture tickets are available. All lecture tickets include a three-day Show pass. 


Guest blog by Renee Enna.
©2016 Chicago Botanic Garden and my.chicagobotanic.org

PHOTO: Peter DeJonge.Peter DeJongh is a first-year master’s student studying land management and conservation in the graduate program at Northwestern University and the Chicago Botanic Garden. His academic focus is on developing strategies to optimize plant and wildlife conservation and restoration. He aims to work in applied conservation or environmental consulting upon completion of his degree.


Imagine a large, beautiful canopy tree standing in the middle of a lush, tropical rainforest. This centuries-old tree produces thousands of seeds every year that densely litter the forest floor around it. Where then would you imagine its seedlings are likely to spring up? Probably in the seed-covered area around the tree right? Well, according to the Janzen-Connell model, you’d be wrong.

Daniel Janzen and Joseph Connell are two ecologists who first described this phenomenon in the early 1970s. They put their exceptional minds to the task and independently discovered that the probability of growing a healthy seedling was actually lower in the areas with the most seed fall. They hypothesized that seed predators and pathogens had discovered the seed feast around the parent tree and moved in, preventing any seeds in the area from growing into seedlings. These predator pests include beetles, bacteria, viruses, and fungi, and have been labelled as host-specific predators and pathogens since they appear specifically around the parent tree, or host.

DIAGRAM: Janzen-Connell hypothesis.

PHOTO: This Malaysian silverleaf monkey eats fruit as part of its diet, dispersing seeds far beyond the canopy line.

This Malaysian silverleaf monkey eats fruit as part of its diet, dispersing seeds far beyond the canopy line.

Janzen and Connell’s hypothesis shows just how important the animals that eat the seeds are to the parent tree. These primates, birds, and other vertebrates move the seeds to different areas where they can successfully grow without being bothered by those pesky host-specific predators. Without these animal helpers, the forest couldn’t continue to grow, and the world’s most diverse areas would be in serious trouble.

Garden post-grads and scientists are in the field working on restoration efforts in the Colorado plateau, fossil hunting in Mongolia, and filming videos on sphinx moths. Interested in our graduate programs? Join us. 


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This is our fifth installment of their exploration.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

PHOTO: Dr. Evelyn Williams, Conservation Scientist.Dr. Evelyn Williams is an adjunct conservation scientist at the Garden. She’s interested in genetic diversity at multiple scales, from the population to the family level. While at the Garden, Dr. Williams has worked on rare shrubs from New Mexico (Lepidospartum burgessii), systematics of the breadfruit family (Artocarpus), and using phylogenetic diversity to improve tallgrass prairie restorations.


When a scientist says that chimpanzees are related to humans, or that chickens are related to dinosaurs, what do they mean?

They mean that chimpanzees and humans share a common ancestor from many thousands of generations ago. Although that shared great-great-great-great-(etc.)-great-parent lived many years ago, that shared ancestor lived more recently than the ancestor that humans share with dogs. So humans are more closely related to chimpanzees than dogs because they have the most recently shared ancestor. Scientists call this the “most recent common ancestor.”

This most recent common ancestor wasn’t a chimp, and it wasn’t a human—it was a different species with its own appearance, habits, and populations. One of these populations evolved into humans, and one of the populations evolved into chimpanzees. We know this because of a field of study called “phylogenetics.” Scientists use phylogenetics to study how species are related to each other. 

Phylogenetic tree diagram.

Using DNA sequences, scientists construct tree-like diagrams that trace how species are related. A human’s DNA is more similar to a chimpanzees’ than to a chicken, so a tree diagram would connect humans and apes. Dinosaurs and chickens would be shown as related as well, and then these two groups would be connected.

Interested in learning more? Explore phylogenetics with the Tree of Life Web Project. Dig deep into the study of the phylogenetic roots of food plants with The Botanist in the Kitchen


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This is our fourth installment of their exploration.

©2016 Chicago Botanic Garden and my.chicagobotanic.org