Science Talk Archive

Exploring the science of plants, from the field to the lab

From War Paint to Candy Bars: An Extraordinarily Versatile Tropical Plant

Posted in Interesting Plant Stories on March 19, 2015 by Ana María Ruiz

Ana María Ruiz is a herbarium data assistant for the William and Lynda Steere Herbarium at the New York Botanical Garden. She is working on the digitization of fungal specimens for the Macrofungi Collections Consortium Project and is a research assistant for the Lichens of the Mid-Atlantic Coastal Plain Project.


Bixa orellana
A plant specimen of Bixa orellana collected in Puerto Rico in 1993 by M. H. Nee, Ph.D.

Bixa orellana, also known as annatto, is a commonly used staple found in kitchens around the world. Everyone at one point or another has consumed it without even knowing it because it is almost tasteless. Used primarily as a food coloring, it has been added to butter, margarine, cheese, cured meats, rice, ice cream, and many other foods.

Nestlé chocolate will soon be added to that list. Nestlé USA recently announced that it was removing all artificial flavors and colorings from all of its chocolate candy by the end of 2015. Instead, the company will begin using annatto, particularly in its reformulation of Butterfinger candy bars. Annatto will provide the natural coloring in the crunchy orange center of the chocolate bar.

The New York Botanical Garden holds collections of the plant and fruit specimens, which can be observed, admired, or studied in the William and Lynda Steere Herbarium. As part of the Steere Herbarium’s digitization projects, the images of the plant and fruit specimens are also available through the Botanical Garden’s C.V. Starr Virtual Herbarium. And live specimens grow in the Lowland Tropical Rain Forest Gallery of the Enid A. Haupt Conservatory.

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Roots: Where The Garden’s Founder Found His Love of Plants

Posted in Nuggets from the Archives on March 13, 2015 by Stevenson Swanson

Stevenson Swanson is the Garden’s Science Media Manager.


Nathaniel Lord Britton New York Botanical Garden
Nathaniel Lord Britton

Nathaniel Lord Britton, the botanist who founded The New York Botanical Garden with his wife, Elizabeth, is so closely associated with this institution in the Bronx that it can come as a surprise to learn that he was a native son of the New York City borough that is most distant from here—Staten Island.

SILive, the Web site of the Staten Island Advance, provided a reminder of Britton’s roots in a recent piece that summarized the eminent botanist’s life and accomplishments.

Born in the New Dorp section of Staten Island in 1859, young Britton developed an interest in botany while growing up in what was then a bucolic setting. The Brittons were a long-established family there: an earlier Nathaniel Britton—whose wife’s name was, coincidentally, also Elizabeth—bought a fieldstone cottage in New Dorp in 1695.

Nathaniel Lord Britton historic Richmondtown Staten Island cottageEventually, Nathaniel Lord Britton and Elizabeth Knight Britton inherited the house, which they owned until 1915, when they deeded it to the Staten Island Institute of Arts and Sciences. It was moved in the 1960s to Historic Richmond Town, a historic town and farm museum, where it remains to this day. Although the Britton Cottage is currently closed to the public, the museum has completed a structure report and hopes to receive city funding to restore it.

By 1915, of course, the Botanical Garden was more than two decades old, leading one to wonder whether the Brittons regularly commuted to the Garden from Staten Island. But no: according to the Garden’s archivist, Stephen Sinon, they occupied the cottage only occasionally, living primarily in a residence on Decatur Avenue in the Bedford Park section of the Bronx, close to the Garden.

Still, the Brittons eventually returned to Staten Island. Dying within a few months of each other in 1934, they are buried in the Moravian Cemetery there.

A Powerful Plant for Fighting a Dreaded Disease

Posted in Interesting Plant Stories on March 12, 2015 by Maya Jaffe

Maya Jaffe graduated from Florida International University and is currently an intern at the William and Lynda Steere Herbarium, where she is working on a project to digitize Thelephora and Agaric mushrooms.


“A handful of qinghao immersed with 2 liters of water, wring out the juice and drink it all.”

That was the recipe prescribed in 340 AD by Chinese alchemist Ge Hong in his A Handbook of Prescriptions for Emergencies as a treatment for malaria (1). For the bulk of human existence, people looked toward the forest and their gardens for remedies for their ailments, just as we now browse the aisles of our local pharmacy. So many of the modern drugs we rely on for our health have botanical precursors. In a way, Ge Hong’s advice still stands today because Quinghao, also known as sweet wormwood (Artemisia annua), contains the chemical compound artemisinin, found in most of the leading antimalarial drugs (2).

Artemisia annua is native to Eurasia and is cultivated on a large scale in China and Vietnam. This member of the Asteraceae (the daisy or sunflower family) is a shrub with a single stem that typically reaches a meter in height and has alternating branches with dissected, fern-like leaves and small, yellow flower heads. And, as the label on this 1957 specimen from the William and Lynda Steere Herbarium notes, “herb has medicinal uses.”

Artemisia annuaherbarium specimen

Ancient Chinese medicine typically utilizes the above-ground parts of the plant, but now scientists have narrowed their focus to the leaves, from which artemisinin can be extracted easily. Because of its chemical composition, artemisinin is highly unstable when warm and therefore has a short shelf life in hot environments. Because of this and the general expense of extraction, Dr. Jay Keasling at the University of California Berkeley is currently exploring the synthetic production of artemisinin (4).

While appreciating modern technology and scientific advances that allow for the development of synthetic drugs, we should recognize and value the medicinal properties inherent in many plants in their natural state, such as sweet wormwood. One way to do that is with The New York Botanical Garden’s Wild Medicine iPhone app, which explores the medicinal properties of various plants throughout the Enid A. Haupt Conservatory.

Next time you’re out in nature and admiring the flora, try to remember that while the aesthetic beauty of plants is breathtaking, those same plants may be vital to every breath that you take.


  1. Tu, Youyou. The Discovery of Artemisinin (qinghaosu) and Gifts from Chinese Medicine. Nature Medicine 17.10 (2011): 1217-220.
  2. White, N. J. “Assessment of the Pharmacodynamic Properties of Antimalarial Drugs in Vivo.” Antimicrobial Agents and Chemotherapy. U.S. National Library of Medicine. 1997.
  3. WHO Monograph on Good Agricultural and Collection Practices (GACP) for Artemisia Annua L. Geneva, Switzerland: World Health Organization, 2006.
  4. Ro, Dae-Kyun, Eric M. Paradise, Mario Ouellet et al. Production of the Antimalarial Drug Precursor Artemisinic Acid in Engineered Yeast. Nature 440.7086 (2006): 940-43.

Sorting Out the Family Trees of Some Vietnamese Trees—Part Two

Posted in From the Field, Travelogue on March 6, 2015 by Douglas Daly

Douglas C. Daly, Ph.D., is the Director of the Institute of Systematic Botany and the B. A. Krukoff Curator of Amazonian Botany at The New York Botanical Garden. Among his research activities, he is a specialist in the Burseraceae (frankincense and myrrh) family of plants.


Bursera tonkinensis_habitat1. Forest on steep slope of karst mountain in Cuc Phuong National Park.
Bursera tonkinensis habitat. Forest on steep slope of karst mountain in Cuc Phuong National Park.

In my previous post about a 3,700-mile expedition through nine provinces in Vietnam, I covered some of the interesting species of the Anacardiaceae (or sumac and cashew family) that my four colleagues and I encountered. But that was only one of the two closely related plant families for which we were searching.

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Citizen Science: Coaxing Life from Frozen Waters

Posted in Applied Science on March 2, 2015 by Madeline Breda

Madeline Breda is a GreenSchool Science Education Intern at The New York Botanical Garden.


In the Thain Family Forest
In the Thain Family Forest

“What is that?”
“What lives in there? Are they dangerous? Do they bite?”
And, loudest of all, “EWWWWWW!”

These are some of the many questions (and noises of disgust) hurled in retaliation to the dripping, mucky leaf pack I hold up at the front of the classroom. Water fresh from the Bronx River streams from the decomposing leaves into a bucket below, and an odor that could be described as either “earthy” or “gross” pervades the GreenSchool classroom. My charges for the next 90 minutes—a group of unsuspecting middle schoolers—want nothing to do with whatever is going on in that mess of organic matter. Little do they know that within minutes they’ll be clamoring to sort through the leaves and rocks and mysterious river sludge to find living treasures underneath…

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Sorting Out the Family Trees of Some Vietnamese Trees—Part One

Posted in Interesting Plant Stories on February 27, 2015 by Douglas Daly

Douglas C. Daly, Ph.D., is the Director of the Institute of Systematic Botany and the B. A. Krukoff Curator of Amazonian Botany at The New York Botanical Garden. Among his research activities, he is a specialist in the Burseraceae (frankincense and myrrh) family of plants.


Habitat of Pentaspadon poilanei on Tien Du Mountain, near Nha Trang City, Khanh Hoa Province.
Habitat of Pentaspadon poilanei on Tien Du Mountain, near Nha Trang City, Khanh Hoa Province

Vietnam is home to a number of species of trees in two closely related plant families, the sumac or cashew family (Anacardiaceae) and the frankincense and myrrh family (Burseraceae), but for decades, many of these species were poorly known and had never been sampled for leaf material for obtaining DNA sequences that would help resolve their evolutionary relationships and contribute to informed decisions aimed at conserving them in the wild.

I was part of a team of five botanists—two from Vietnam and three from The New York Botanical Garden—who conducted a joint expedition in April and May of 2010 in search of trees belonging to these two important plant families. Drs. Le Dong Tan and Nguyen The Cuong represented the Vietnam Academy of Science and Technology/Institute of Ecology and Biological Resources, and the Botanical Garden was represented by Dr. Susan Pell, John Mitchell, and me.

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Late Bloomer: The Short, Prolific Career of Ynes Mexia

Posted in Nuggets from the Archives on February 26, 2015 by Elizabeth Kiernan

Elizabeth Kiernan is a project coordinator for the William and Lynda Steere Herbarium at The New York Botanical Garden. She is currently working on a program to document the biodiversity of the Amazonian region of South America.


A photograph of Ynes Mexia in the field
A photograph of Ynes Mexia in the field

Ynes Mexia, a Mexican-American botanical collector and explorer who began her career in 1925, became the most accomplished female botanical collector of her time both in terms of the number of plant specimens she collected and the miles she traveled on her expeditions. Although she began in her mid-50s and her career was relatively short, she was able to collect an incredible 145,000 specimens. Of those, 500 were new species, and 50 were named in her honor. The William and Lynda Steere Herbarium is fortunate to have many of her specimens.

Mexia was born on May 24, 1870, in Washington, D.C. There are varying accounts of Mexia’s early life, but it is agreed that it was somewhat tumultuous. When she was very young, her parents divorced. Her father returned to his native Mexico, and her mother moved the family to Texas. She was married twice: her first marriage ended abruptly with her husband’s death, and her second marriage ended in divorce. After her divorce, she moved from Mexico City to San Francisco and became involved in social work. She also became an active member of the Sierra Club, which motivated her to attend the University of California, Berkeley.

Her interest in botanical collecting began in 1922 when she joined an expedition led by E. L. Furlong, a Berkeley paleontologist. She enrolled in a course on flowering plants at the Hopkins Marine Station in Pacific Grove, California, and soon after embarked on her first botanical exploration trip to Mexico with Stanford botanist Roxana Ferris. Once in Mexico, Mexia decided that she could accomplish more on her own and abandoned the group, traveling the country for two years and collecting more than 1,500 specimens. She made three additional expeditions to Mexico and collected throughout South America in remote areas of Argentina, Brazil, Bolivia, Ecuador, and Peru. She also collected in Alaska and other areas of the United States.

One of the highlights of her explorations was canoeing the Amazon River from its delta to its source in the Andes, covering nearly 3,000 miles in two and a half years. Her specimens were widely distributed to herbaria throughout the U.S. and Western Europe. In addition to collecting, Mexia wrote articles and gave lectures describing her adventures and travels. She died of lung cancer in 1938.

Credit is due to Nina Floy Bracelin, affectionately known as Bracie, who prepared Mexia’s specimens for herbaria. She worked diligently to label the specimens, sending sets to specialists so their species could be determined and distributing the duplicates. Mexia was said to be more interested in exploration and discovery rather than preparing her specimens, but her legacy lives on through those preserved botanical collections, including those that can be found today in the Steere Herbarium.

Saurauia mexiae Steere Herbarium type specimen
This specimen of Saurauia mexiae in the Steere Herbarium was collected by Mexia and named in her honor. It is a “type specimen,” which is a specimen selected to serve as a reference point when a plant species is first named.

For more information, please refer to:

“Mexia, Ynes Enriquetta Julietta (1870-1938).” JSTOR Global Plants. http://plants.jstor.org/stable/10.5555/al.ap.person.bm000033443

Bracelin, N. Floy. 1982. “The Ynes Mexia Botanical Collections,” an oral history conducted in 1965 and 1967 by Anetta Carter. Regional Oral History Office, The Bancroft Library, University of California, Berkeley. http://archive.org/stream/ynsmexabotan00bracrich/ynsmexabotan00bracrich_djvu.txt

Radcliffe, Jane. “Ynes Mexia (1870-1938): Biographical Sketch.” California Academy of Sciences, http://researcharchive.calacademy.org/research/library/special/bios/Mexia.pdf

“Ynes Mexia Collection, 1918-1966.” University and Jepson Herbaria Archives, University of California, Berkeley. http://ucjeps.berkeley.edu/archon/?p=collections/findingaid&id=77&q=&rootcontentid=7350

Documenting Plant Diversity: Using a Flora to Describe Flora

Posted in Applied Science on February 20, 2015 by Scott Mori

Scott A. Mori, Ph.D., is a Curator Emeritus associated with the Institute of Systematic Botany at The New York Botanical Garden. His research interests are the ecology, classification, and conservation of tropical rain forest trees.


Two graphs showing the history of plant collection in central French Guiana. A. Progressive accumulation of vascular plant species known from the flora of central French Guiana from 1950 to 1999. B. As the species of the area became better known each of the collections became more valuable because of the new information it provided.
Two graphs showing the history of plant collection in central French Guiana. A. Progressive accumulation of vascular plant species known from the flora of central French Guiana from 1950 to 1999. B. As the species of the area became better known each of the collections became more valuable because of the new information it provided.

Among the many products of the research published by scientists at The New York Botanical Garden (NYBG) are Floras. A Flora is a book in which species are described, while the word flora refers to the totality of plant species in an area; in other words, a flora is described in a Flora.

Floristic publications document and describe the diversity of a given group of plants growing in specific geographic areas. They may be floras of algae, mosses, ferns, gymnosperms, and angiosperms or combinations of these groups. For example, a Flora might include all of the vascular plants (ferns, gymnosperms, and angiosperms) of the northeastern United States. The equivalent of a Flora for fungi is called a Mycota, because fungi are more closely related to animals than they are to plants.

Some examples of Floras are the Manual of Vascular Plants of Northeastern United States and Adjacent Canada by Henry A. Gleason and Arthur Cronquist, the Intermountain Flora recently completed by Noel and Patricia K. Holmgren and their colleagues, and Pleurocarpous mosses of the West Indies by William R. Buck–all published by The New York Botanical Garden Press. Floras are important because they allow both amateur and professional botanists to identify plants—the first step in developing a deeper appreciation of plants and for carrying out research on them. In addition, scientific Floras or Mycotas serve as the basis for field guides such as Roy Halling and Gregory M. Mueller’s Common Mushrooms of the Talamanca Mountains, Costa Rica.

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A Salute to Jackie Kallunki

Posted in Personalities in Science on February 19, 2015 by Barbara Thiers

Barbara M. Thiers, Ph.D., is the Patricia K. Holmgren Director of the William and Lynda Steere Herbarium and Vice President for Science Administration at The New York Botanical Garden.


Jacquelyn A. Kallunki, Ph.D.
Jacquelyn A. Kallunki, Ph.D.

Jackie Kallunki, Ph.D., first came to The New York Botanical Garden in late 1975 and worked for a while identifying neotropical plant specimens and gathering data for an ethnobotanical project. At that time, she was still working on her Ph.D. dissertation at the University of Wisconsin. After she completed her dissertation, she came back to the Botanical Garden as a full-time employee. And now, I’m sad to say, she has retired.

Over the years, as Jackie rose through the ranks to become Assistant Director of the William and Lynda Steere Herbarium, she worked closely with Patricia K. Holmgren, Ph.D., who was then Director of the Herbarium. This was a very active period in the Herbarium’s history in terms of acquisitions, loans, visitors, and special projects such as the incorporation of orphaned herbaria and expansion of the collection.

The crowning achievement of this period was the planning of the new Steere Herbarium and then moving the multi-million-specimen collection into it. Jackie was the one who figured out how much space each group of plants should receive and where it should go, and she supervised the highly complicated process of moving the specimens to the Herbarium. It took 58 Garden staff, interns, and volunteers a total of about 3,300 hours to accomplish this move. The fact that the process went smoothly and according to schedule is a testament to Jackie’s planning abilities, determination and powers of intimidation!

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Four “Flavors” of New Plant Species, Part Four

Posted in New Plant Discoveries on February 13, 2015 by Benjamin Torke

Benjamin M. Torke, Ph.D., is an Assistant Curator at the Garden’s Institute of Systematic Botany. His specialty is legumes, a large plant family that includes not only beans and peanuts but also hundreds of rain forest tree species.


Rare. Restricted. Remote. Those are three characteristics, or “flavors,” of the new species that plant scientists discover and describe every year. Breaking our pattern, the fourth and final flavor in this series does not begin with an “r.” Some new species are cryptic.

The most recent comprehensive taxonomic treatment of Swartzia was written by the late Dr. Richard Cowan, curator of legumes at The New York Botanical Garden during the 1950s. In that seminal work, Cowan brought order to chaos. Previous authors had given numerous scientific names to the same species. Cowan recognized one name for each species and classified the other names as synonyms. In at least one case, however, it appears that he may have gone a bit too far.

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