She's the most accomplished female plant collector of her time.

And she did not start until she was 55 years old.

1929, Brazil.

59-year-old Ynés Mexía undertook the greatest adventure of her career -- a two-and-a-half-year expedition, traveling 3,000 miles up the Amazon River by steamship and canoe.

She went out collecting by herself, with a guide because she realized that you can't go off into the wilderness totally by yourself because you don't know the terrain.

Of course being fluent Spanish, she can talk to all these guides.

And it was interesting because she'd teach her guides how to do some of the pressing.

"After more than two years in the wilds of South America, I find myself longing for a nice, quiet jungle again."

Ynés Enriquetta Julietta Mexía was born in 1870 in Washington, DC, where her Mexican father was stationed as a diplomat.

At one year old, she moved to Mexia, Texas, a town founded by her ancestors.

Ynés was very shy, very quiet.

Liked to keep to herself, read a lot of books.

Her parents separated when Ynés was nine and immediately put her into a private boarding school.

And so Ynés' early life was probably very painful, because she just was all by herself.

After finishing her studies, Mexía considered entering a convent, but in 1896, her dying father asked her to take over his business in Mexico.

He has a huge ranch, he is quite wealthy.

She takes over the managing of the ranch and becomes a very adept.

Mexía married twice.

Her first husband died after a long illness.

Her second bankrupted the ranch.

And at that point, it's just too hard on her.

She literally goes into bed and crawls up in a fetus position.

It's a mental and a physical breakdown.

In 1909, Mexía moved to San Francisco to seek medical help from Dr. Phillip King Brown.

He was a psychiatrist.

That was a very new field in 1909.

He became the father figure that she never had.

Mexía remained under Dr. Brown's care for 10 years.

At his encouragement, she joined California's budding environmental movement.

She became a valuable part of the Sierra Club and Save the Redwoods League on the forefront of fighting for the national parks.

"I have been much distressed to hear cutting has been going on in Montgomery Grove.

I'm heartily in sympathy with any effort to save these trees."

This shy woman joins this outgoing club with excursions to the Redwoods and excursions to Yosemite, and camping out and going on hikes.

And she just loves it.

Mexía decided to pursue science and natural history courses at UC Berkeley.

This is 1921, no woman goes back to college at 51 years old, but she did.

And she discovered botany.

Suddenly here was the life goal that she had never realized before that she would have and she loved collecting plants.

"I have a job where I produce something real and lasting."

Women were to be confined to the kitchen, the garden, and the baby room.

So botany was more acceptable for women scientists because it's a logical extension of women being caretakers.

My name is Ina Vandebroek.

I'm an ethnobotanist at the New York Botanical Garden.

Plants are really the essence of human life.

Without plants we do not have oxygen.

Without plants we do not have food.

And at least one in four of our medicines is made from plants.

In 1925, Mexía took her first plant collecting trip to Mexico, on a group expedition sponsored by Stanford University.

But she soon realized she could be more productive alone.

She secured funding from several natural history institutions willing to pay her 20 cents per specimen.

56 years old and never stopped after that.

She went into Mazatlan, and then into the Sierra Madre mountains.

"My driers get all filled up and still numberless plants sit and look at me and announce that they're waiting to be collected.

It is terribly trying to greedy collector like myself."

Her trip didn't end exactly as she had planned because she saw a plant, reached over to get it, and fell down a cliff and got a few ribs broken and I think an arm.

Nonetheless, the expedition resulted in 500 plant specimens.

One of them, Mexianthus mexicanus, became the first of many named in her honor.

Mexía's reputation as the first Mexican American female botanist grew, and botanical institutions around the U.S. sponsored her expeditions.

For the next 12 years, Mexía collected plants across North and South America, from Alaska to Tierra Del Fuego.

"A well known collector and explorer stated very positively that 'It was impossible for a woman to travel alone in Latin America'... Well, why not?...I decided to make my way right across it."

Ynés very much did what botanists are doing now, minus the technological developments like DNA analysis, collecting plants, naming them, describing them, classifying them.

Which is the basic building block of all biodiversity science.

One third of all the 450,000 estimated flowering plants that exist on earth are under threat of extinction.

There is urgency to protecting that plant diversity, because we need them for our survival.

On her last expedition in Mexico in 1938, Mexía became sick and was soon diagnosed with lung cancer.

She died a few months later at age 68, leaving much of her estate to the Sierra Club and the Save The Redwoods League.

In a 13 year career, she collected more than 145,000 specimens.

A new genus was named for her and then she had 50 other new species named after her, plus 500 other discoveries.

Over the last three decades, there has been a lot of talk about including women in STEM, science, technology, engineering, and maths, and progress has been made, but we still have a long way to go.

Especially the representation of women from immigrant communities and women of color in science, to be in leadership roles, be recognized for their contributions.

"In all of my travels I've never been attacked by a wild animal, lost my way or caught a disease...

I don't think there's any place in the world where a woman can't venture."