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

Daniel Atha

Unwelcome Import: New Invasive Plant Found at NYBG and in Manhattan

Posted in New Plant Discoveries on May 12, 2017 by Daniel Atha

Daniel Atha is the Director of Conservation Outreach for NYBG’s Center for Conservation Strategy at The New York Botanical Garden.


Photo of Italian arum
Italian arum (Arum italicum)

Italian arum (Arum italicum) is a European species popular with gardeners because it is shade-tolerant, deer-resistant, and sports lush foliage through the winter months when little else is green. Now, however, it appears to have escaped from cultivation and established itself as an invasive plant in several natural areas in New York City, including The New York Botanical Garden—the latest in a series of invasive plant species that are threatening our native species. 

A low, herbaceous plant related to our native jack-in-the-pulpit (Arisaema triphyllum) and skunk cabbage (Symplocarpus foetidus), Italian arum forms dense patches and spreads by underground tubers and by seeds encased in bright red fruits attractive to birds. The plants produce several compounds toxic to mammals, including saponins, calcium oxalate, alkaloids, and others. It has become a dangerous pest in the Pacific Northwest and is classified as a Class C noxious weed in Washington State. On Lopez Island, Washington, conservationists have been trying to eliminate a two-acre infestation with little success. The species has shown remarkable resistance to herbicide treatment, and repeated cutting has had no effect.

Read More

Roaming the Wilds of Early 19th-Century Manhattan and Beyond—and Taking Notes

Posted in Nuggets from the Archives on April 19, 2017 by Daniel Atha

Daniel Atha is the Director of Conservation Outreach for the Center for Conservation Strategy at The New York Botanical Garden.


Photo of John Torrey's Portrait
Portrait of John Torrey by David Huntington, 1857. From the collection of Princeton University. Image from the LuEsther T. Mertz Library/The New York Botanical Garden

The New York Botanical Garden has been a leader in the development of modern methods for the study of phenology, the seasonal changes that plants and animals undergo every year. Beginning in the early 2000s, staff and volunteer citizen scientists have been monitoring changes in leaf, flower, and fruiting times throughout the year and from year to year. The methods and data developed at NYBG were eventually incorporated into the National Phenology Network’s national program, which today includes hundreds of partners and thousands of observers in all 50 states.

The NYBG’s legacy goes back even further—in fact, almost to the founding of the nation. While many of the founding fathers were still alive (and many had homes in and around New York City), a young medical graduate, John Torrey, was roaming the wilds of Manhattan, Brooklyn and nearby New Jersey, documenting pitcher plants, lady slipper orchids, white cedar swamps and many other botanical rarities now found only far to the north in colder, less disturbed habitats. As a scientist and natural historian, Torrey was meticulous about his methods, and he endeavored to broaden the impact of his work by including new and helpful information such as detailed locations and precise flowering times of the plants he found. In 1899, John Torrey’s herbarium and papers passed from Columbia University (where he was a curator) to The New York Botanical Garden.

I have recounted the story of Torrey’s phenological record of plants in and around early 19th century New York for the Biodiversity Heritage Library (BHL), a consortium of research libraries dedicated to digitizing the literature of biodiversity and making it accessible in a global “biodiversity commons.” A digitized copy of his record, which he called Calendarium Florae for the Vicinity of New York, was recently added to the library’s online resources. You can read the BHL post here.

The Pumpkin Ash: An Update on a Rare New York Tree

Posted in New Plant Discoveries on November 21, 2016 by Daniel Atha

Daniel Atha is Director of Conservation Outreach for the Center for Conservation Strategy at The New York Botanical Garden.


Jim Coelho with pumpkin ash near the Bronx Zoo’s Reptile House. (Photos by Daniel Atha)
Jim Coelho with pumpkin ash near the Bronx Zoo’s Reptile House. (Photos by Daniel Atha)

I previously reported on the discovery of pumpkin ash trees in Central Park, expanding the known range of the species into Manhattan. Now, recent discoveries have expanded the range of the species in the Bronx as well, bringing the number of known populations of this rare tree in New York to five (four in the Bronx and one in Manhattan).

In 1903, Nathaniel Britton, co-founder of The New York Botanical Garden and one of the most influential botanists of the 20th Century, collected a specimen of a “wild” ash tree in what was then the Botanical Garden’s “North Meadow” (the site is now in the Bronx River Forest section of Bronx Park). Britton named the tree Fraxinus michauxii for André and François Michaux, a father-and-son team of 19th-century French botanists sent to catalog the arboreal treasures of North America. Taxonomists now consider Britton’s tree only a minor variant of Fraxinus profunda (the pumpkin ash) and not worthy of species distinction. The tree from which he collected the specimen is now gone, but its descendants are alive and well in the region, as we are discovering.

Read More

A Surprising Find in Central Park

Posted in New Plant Discoveries on August 5, 2016 by Daniel Atha

Daniel Atha is the Conservation Program Manager at The New York Botanical Garden. He leads the Botanical Garden’s collaboration with the Central Park Conservancy on the Central Park Flora project.


Pumpkin ash tree recently discovered in Central Park
Pumpkin ash tree recently discovered in Central Park (Photos: Ken Chaya)

In the middle of Central Park, in the heart of North America’s largest metropolis, one of the rarest trees in New York has begun to set fruit, making it possible to determine its true identity. Working with arborists from the Central Park Conservancy, botanists from The New York Botanical Garden recently confirmed the occurrence of two pumpkin ash trees (Fraxinus profunda), a species that is endangered in New Jersey and Pennsylvania and was only recently added to the New York flora.

As part of the Central Park Flora project—a three-year endeavor to document the wild flora of Central Park—the team has discovered white ash (Fraxinus americana), European ash (Fraxinus excelsior), two varieties of green ash (Fraxinus pennsylvanica var. pennsylvanica and Fraxinus pennsylvanica var. subintegerrima) and now pumpkin ash growing wild in Central Park.

Read More

NYBG Scientists Help Discover a Promising Anticancer Agent to Fight a Childhood Scourge

Posted in Interesting Plant Stories on March 30, 2016 by Daniel Atha

Daniel Atha is the Conservation Program Manager at The New York Botanical Garden.


A chemical agent found in a member of the snapdragon family (Scrophulariaceae) has shown early promise as a potential treatment for a cancer whose victims are overwhelmingly infants and children.

I recently co-authored a paper describing the potency of a chemical extracted from Armenian figwort (Scrophularia orientalis) in killing malignant cells found in neuroblastoma, a cancer of the nervous system. Neuroblastoma is the most common non-brain solid tumor in children and the most common cancer in infancy (NIH NCI, 2016). Almost half of its victims are children under two years of age.

Read More

A Most Unlikely Place for a BioBlitz

Posted in Learning Experiences on September 18, 2015 by Daniel Atha

Daniel Atha is the Conservation Program Manager at The New York Botanical Garden. Richard Abbott, Ph.D., is a botanist at the Botanical Garden, where he works primarily on updating the Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Donald McClelland, Ph.D., studied at the Garden and is currently Adjunct Assistant Professor at Baruch College.


Freshkills Park
Freshkills Park

Feeling like astronauts exploring an alien planet, the three of us conducted botanical investigations on the capped and newly vegetated mountains of garbage that is Freshkills Park—once the largest landfill in the world. Resembling a moonscape, only with methane-capturing wells and a thick mantle of grass, the mound at Freshkills Park is soon to become a public recreation area.

Read More

A Day in the Life of the Bronx River

Posted in Interesting Plant Stories on December 17, 2014 by Daniel Atha

Daniel Atha is a Research Associate at The New York Botanical Garden.


In canoe from left: Elaine Feliciano, NYC Parks, Conservation Crew Leader, Bronx River Alliance and Adam Felber, Bronx River Alliance. In the foreground is common pondweed (Elodea canadensis), one of the native species found.
From left: Elaine Feliciano, NYC Parks, Conservation Crew Leader, Bronx River Alliance and Adam Felber, Bronx River Alliance. Foreground: common pondweed (Elodea canadensis), one of the native species found during the Bronx River Survey.

Plants that grow beneath the surface of streams and other bodies of water are easy to overlook, but they play important roles in aquatic ecosystems. They help clean and oxygenate water, stabilize fragile stream-beds, and provide food and habitat for aquatic and wetland creatures, including insects, fish, and waterfowl.

Examples of submerged aquatic plants include native pondweeds, coontail, and eel-grass. But some species—milfoil, fanwort, curly pondweed, hydrilla, and others—may become invasive, choking waterways, consuming oxygen, and reducing biodiversity.

In August, a team from The New York Botanical Garden, the Bronx River Alliance, and the New York City Department of Parks and Recreation surveyed the upper reaches of the Bronx River, looking for native and invasive species of submerged aquatic plants. The survey was jointly organized by NYC Parks, the New York-New Jersey Harbor & Estuary Program, the Bronx River Alliance, and representatives from other federal, state, city, university, and community organizations.

Read More

Detecting an Invasive Plant Before It’s Too Late

Posted in Interesting Plant Stories on July 3, 2014 by Daniel Atha

Daniel Atha is a Research Associate at The New York Botanical Garden. Jessica Schuler is Director of the Botanical Garden’s Thain Family Forest. Sarah Lumban Tobing is a Project Manager for Forestry, Horticulture and Natural Resources at the New York City Department of Parks and Recreation.


Purple keman (Corydalis incisa)
Purple keman (Corydalis incisa)

The latest threat to our local environment comes from an Asian plant that resembles wild chervil when young and has the potential to out-compete native species.

A member of the fumitory family, Corydalis incisa, or purple keman, is native to China, Korea, and Japan. It was first discovered growing wild in North America during the 2005 Bronx Park BioBlitz, north of The New York Botanical Garden.

A rapid survey of the same area in May revealed populations on both sides of the Bronx River and extending throughout the annual floodplain, consisting of both first-year seedlings and second-year flowering and fruiting plants. Within one heavily infested area, 32 seedlings were counted in an area of 100 square centimeters (a little more than 15 square inches).

Also this year, we found a previously undocumented infestation, 7.5 miles northeast in the Bronx River Reservation of Westchester County, representing the second known population in North America and the first report of the species for Westchester County.  The sighting was immediately reported to Westchester County Parks Department and we are now working with Brenda Bates of the Conservation Division to document and monitor the plants.

Read More

The Body Electric

Posted in Nuggets from the Archives on December 6, 2013 by Daniel Atha

Daniel Atha is an Associate Editor of NYBG‘s systemic botany journal, Brittonia, and a researcher specializing in floristics, taxonomy, and economic botany. He has taught classes in anatomy and systematics at the Garden’s School of Professional Horticulture and is currently working on a project to develop identifying DNA barcodes for plants of the Northeastern United States.


“I knew a man, a common farmer, the father of five sons,
And in them the fathers of sons, and in them the fathers of sons.”

– Walt Whitman, “I Sing the Body Electric,” from Leaves of Grass, 1855

Urtica dioica L. (stinging nettle)
Urtica dioica L. (stinging nettle)

If told there was a substance promising that each of our five sons, and each of their five sons would grow up to be “massive, clean, tan-faced, handsome,” would we approach that substance with caution, treating it with respect and gratitude? Or would we rush out, blindly gathering as much as we could? Well… Mother Nature must have seen us coming because, while she created just such a material, she cleverly devised a way to ensure we respect it.

The “substance,” of course, is stinging nettle. And of all the matter on earth, nettles come impressively close to providing our every need in one convenient package. Nettles help us grow strong and they keep us healthy. Along the way they feed us, clothe us, transport us, and soothe our pains. Want more? They give it, body and soul, sacrificing all for the next generation.

Nettles are a “perfect food,” containing vitamin A, vitamin B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (panothenic acid), vitamin C, vitamin D, vitamin E, vitamin K, acetycholine, calcium, chlorophyll, chromium, iron, magnesium, potassium, selenium, serotonin, sulphur and zinc. And like only a handful of plants, they pack plenty of protein. Fortified with nettles, our immune systems have what they need to keep us healthy and our brains have the neurotransmitters to keep us happy. The flax-like stem fibers have clothed us in soft, durable fiber from neolithic loincloths to WWI army uniforms, even providing a dye to make them green.

Read More

Central Park’s Plant Life: More Diverse Than Ever

Posted in New Plant Discoveries on November 4, 2013 by Daniel Atha

Daniel Atha, a research associate at The New York Botanical Garden, coordinated the botanical component of the recent Central Park BioBlitz, an intensive biological inventory of the park.


With woodlands, meadows, ponds, and gardens, New York’s Central Park hosts a greater diversity of plants and animals than most people probably realize. Assessing this diversity was the goal of the 2013 Central Park BioBlitz in late August, when more than 400 professionals, students and citizen-scientists documented the park’s flora and fauna over a 24-hour period.

Central Park BioBlitz
Daniel Atha presses plant specimens collected during the Central Park BioBlitz.

The results are in, and they show the park is becoming more diverse despite an exponential increase in visitors to nearly 40 million per year. Chipmunks and lichens are coming back, and the waters are clean enough to support catfish and crappie—native species usually found in more rural areas.

Read More