The grass was way too high for a picnic. So drivers headed east from Gary, passing the vacant land along the south rim of the Indiana Toll Road that Saturday afternoon in early August, must have assumed they were looking out over some kind of grisly crime scene. Why else would a cluster of seven adults, two in vaguely military-style uniforms, be wading slowly through waist-high weeds, armed with clipboards, heads down?

If they had been driving by slowly enough, they could’ve seen that every few minutes one of the detectives would suddenly drop to all fours, followed by the rest of the group, and the hunt would proceed at ground level for a while. The team seemed to be looking for footprints or scrape marks–some kind of clue.

But the detectives were only botanists and park rangers, and the mystery that had them tramping around among the joe-pye weed and the wild bergamot was not a crime. Instead it was possibly the most perplexing and enduring mystery in the Chicago region’s natural history. It’s a two-sided riddle, one side of which has been nagging botanists for 82 years, the other only four years fewer.

The first question is: Where did the tiny translucent blue green flower known by the Latin name Thismia americana come from?

The second is: Where did it go?

On August 5, 1912, a botany professor-to-be discovered Thismia in a prairie near 119th Street and Torrence Avenue, half a mile north of what’s now Ford Motor Company’s big southeast-side plant. On her hands and knees collecting moss specimens for use in the classroom, Norma Pfeiffer found a pale bluish white flower no bigger than the eraser on a pencil popping out of the moss and leaf litter. It turned out to be the rarest plant ever found growing wild in Chicago; its nearest botanical relative grows in New Zealand, and even its cousins don’t come any closer than Panama. Pfeiffer analyzed the plant for four years, but the last time she–or anyone–saw Thismia alive was on September 1, 1916.

Looking for Thismia is the local botanical crowd’s version of waiting for Godot. Some have no doubt that Thismia will soon show up on a forgotten remnant prairie. Others want to believe but aren’t sure they can. And a few, certain Thismia is never coming back, play along, not wanting to pronounce something dead just because they haven’t seen it.

“I think it would be arrogant for us to presume that Thismia is extinct simply because several well-trained botanists with big egos haven’t discovered it,” says Dr. Gerould Wilhelm, a well-trained botanist with the Morton Arboretum. Wilhelm is coauthor of an exhaustive scientific guide to all 2,530 plant species growing naturally in the Chicago region, and since 1991 he’s been a fixture at the annual Thismia Hunt. But like an atheist in a roomful of Bible-thumping in-laws, Wilhelm carefully avoids giving his opinion on the existence of Thismia.

“Our ignorance of the plant’s historic and present distribution doesn’t have much to say about its actual distribution. It merely means that we are ignorant of Thismia’s habits. It doesn’t mean the plant isn’t growing by the thousands out there.”

Even thousands of wild Thismia growing together would be virtually invisible to nearly anyone other than a botanist looking for them. It’s not only a small plant, but also a clandestine one. According to the studies Pfeiffer did for her doctoral dissertation, the plant grows mostly underground and may be visible only when it’s in flower. Pfeiffer, who never saw any above-ground leaves or stalks, determined that Thismia is a saprophyte, a plant that grows in dead or decaying organic matter like the discarded leaves and dried mosses that collect on the soil’s surface around the base of prairie grasses and flowers. It has no chlorophyll, the stuff that makes plants green, so it doesn’t have any reason to emerge from the soil until it’s ready to be pollinated by insects.

“A child might find it by accident,” says botanist Linda Lobik, a Thismia Hunt regular. Each year she wears a necklace ornamented with a life-size white plastic replica of the Thismia bloom. “I always hoped my son would find Thismia while he was playing in the dirt.”

Manfred Ruddat, an associate professor in the University of Chicago’s ecology and evolution department, argues that if Thismia is alive, it ought to be left alone. “If you have a lot of botanists trampling around where a rare and very small organism may have lived, it’s not unlikely that somebody inadvertently stepped on it, sending it to its absolute demise. Some very well meaning person may have just crushed it. That would be unfortunate.”

But Wilhelm, who has spent two decades identifying and classifying Chicago’s native plants, says searching for Thismia is scientifically legitimate. Because only a tiny sliver of the midwest’s native landscape remains unplowed, undeveloped, or unpoisoned by the march of progress, finding the inconspicuous little native might say a lot about the state of the planet. “That something [like Thismia] still survives would say something very special about the location where it was found,” he says. “It would signify that there is still a little bit of living earth tissue left in this part of the world.”

Besides, getting a bunch of botanists together to look closely at remnant prairies has other valuable results. The first three Thismia Hunts added 50 species to the list of plants that can be found in undeveloped areas of the Lake Plain Region, a slab of land off the southwestern tip of Lake Michigan. None of those species has the mystery or drama of Thismia, but they’re additions to the big ball of scientific understanding, where any new knowledge is good knowledge.

On August 6, five cars caravanned through a Mad Max landscape of crumbled asphalt, weeds, and sunbaked dirt, ferrying one of this year’s Thismia Hunt teams through the mostly empty grounds of the once-huge Du Pont factory in Hammond. The plan was to search the back edge of the property, which the chemical firm never developed.

From the command post at Gibson Woods Nature Preserve in Hammond, six teams of up to 15 people each were set to fan out to scattered patches of prairie, including the Du Pont site and others close by. Each team would scour a different piece of ground, all identified by botanists or park rangers as likely haunts for the botanical ghost. Specifically, the territory they were to inspect resembled the ground Pfeiffer described and photographed: low-growing moss cover and some exposed soil.

Scientists assume that a plant is likely to show up where its associate species are. Pfeiffer named 11 associates that grew near her discovery; a prairie that sports most or all of those is a likely spot for a reunion. The original location was eliminated as a possible site decades ago, when a lot of heavy industry came to that part of Chicago. Wilhelm and others estimate that at least three feet of industrial ash and other gunk covers the native soil now–far too much for little Thismia to climb through. But any moist prairie setting with acid-free soil within ten miles of the original site is a good candidate. Some of them are dedicated nature preserves; others, like the DuPont property, are privately owned but have somehow managed to avoid being developed.

The group at Du Pont included a Nature Conservancy botanist who studies plants of the Great Lakes region and last spring coauthored a highly publicized report cataloging the biodiversity of the region; another botanist who is cataloging all plants native to Will County for the forest preserve district there; an Environmental Protection Agency scientist; a painter; and a handful of others.

At 10:45 AM the group left the cars on a dusty scrap of asphalt and started out on foot through a gorgeous, sun-drenched landscape dominated on one side by a sand ridge topped with muscular black oak trees and on the other by ten-foot cattails quivering in the gentle breeze. The slope in between was painted with the purple rocket-shaped blooms of wild vervain, lavender bunches atop joe-pye weed, the honey gold and black heads of black-eyed susans, and assorted greens, from the spiky rattlesnake master to the grassy, almost fluid knee-high sedges. “I look at a landscape like this and feel wistful about what it must have looked like when the Native Americans were alone here,” said Sue Crispin, the Nature Conservancy botanist. “It’s like going back in a time tunnel.”

But a half mile later the outing started to feel more like a fraternity-initiation ritual than an ecological joyride: at random intervals the hunters suddenly stepped off the trail and dropped to all fours in the sedges. I started to wonder who was going to paddle us and force cheap liquor down our throats, but Ken Johnson, the Will County botanist, reassured me that this was the way it was done.

“That’s what botanizing is all about,” said Johnson, a lean man almost as tall as the cattails. “It’s not glamorous–it’s getting off the beaten paths, getting down in the mud, and seeing what lives there.”

A shout bubbled up from the sedges 20 yards away: “Hey, we found Selaginella!” Two hunters had found a type of moss that Pfeiffer identified as one of Thismia’s usual neighbors. Selaginella is a category that includes 700 different species of mosses; of those, the one species that could signal the proximity of Thismia is Selaginella apoda. I wandered over and asked one of the pair how, exactly, a person can tell one moss species from another. “I saw Pfeiffer’s photographs, and I’m looking very closely at this moss,” the hunter told me with a slight edge in his voice. Two hours later some members of another search party were grousing that they hadn’t found any good target spots that day–in fact, they hadn’t even seen the right Selaginella. I volunteered that somebody had showed it to me at the Du Pont site. Oh really? the hunters asked. Who found it? I rifled through my notes to find his name, and when I told them, several members of the team shrugged. One leaned over to tell me, “He’s a really nice man, but you didn’t see Selaginella.”

When Norma Pfeiffer first found Thismia in 1912, she was doing exactly what modern botanists who are looking for the plant do: she was crawling around in the mud. A key difference, as more than one female hunter pointed out on Thismia Hunt day, is that Pfeiffer would have been wearing a long dress. The fact that these days women botanists, just like their male colleagues, mostly wear jeans to do this kind of work would have meant a lot to Pfeiffer, who was a lifelong “women’s libber,” according to her nephew Ralph Wood, a Chicago financial planner.

In fact, Pfeiffer’s discovery itself has some ironic feminist undertones. In a letter to a friend in 1984, Pfeiffer explained that she had gone to the open prairie to collect specimens she could use in the classroom at the University of North Dakota, where she would begin teaching the next month. The prairie at 119th and Torrence, known as Solvay, was the site of frequent expeditions by University of Chicago botany classes at the time, so Pfeiffer and a friend who was also about to start a teaching job “made several collecting trips together to have stuff on hand, if our colleges lacked it,” she wrote. When she arrived in Grand Forks several weeks later, she found out that “the man who has the head of the botany department was married to a woman in fragile health,” her nephew says. “The deal for Norma was, ‘You’ll live in our house and you’ll teach a class, and you’ll also be the maid for my wife.'”

It was the second time she had been disappointed that summer; the first job offer she’d gotten had been from Knox College in Galesburg, Illinois. Wood says the offer was rescinded a few weeks before she was set to move downstate because “they had found a man to take the job after all.”

At the time, the thrill of knowing she had found the most bizarre plant in North America must have been little consolation for Pfeiffer. The process of identifying the little weirdo and determining its exact spot on the enormous family tree of the world’s flora was a slow and painstaking one. As Crispin says, “All she could have known at first was that she had found something that seemed strange. It would be a long time before she could know exactly how strange it was. Botanists are patient–they have to be.”

The University of Chicago’s botany professors–at that time some of the major figures in American plant science–gathered over Pfeiffer’s find and pronounced it worthy of her doctoral thesis. “I already had a [thesis] problem,” Pfeiffer wrote in the 1984 letter, “a difficult one because my instructor thought I was young (early 20’s) and had time; some candidates for Ph.D’s were near 50.” Twenty-three-year-old Pfeiffer discarded her original thesis question, went back to the prairie to collect more specimens, and trundled them off to Grand Forks.

“I worked alone all year on its structure, etc–pure research,” Pfeiffer wrote. “The library was small and gave no clues. So when I went back to Chicago for the summer, first day went [sic] to the scientific library, where I found it belonged to a family of plants that grow mostly in the tropics. But it had never been described, so I could name it and describe it for my thesis.”

Pfeiffer had collected a small conical flower whose open end looks something like a six-pointed star with three points folded over the mouth and three points extended. All that protruded from the ground was the six-pointed cap, one-tenth to two-tenths of an inch high and wide. And that may only have happened between July 25 and September 8, the earliest and latest dates she recorded seeing it over the next few years. The plant’s whitish root system and leaves stayed underground.

Pfeiffer gradually determined that the plant was a member of the botanical family Burmanniaceae, whose members mostly grow in very wet tropical forests. Stranger still, it belonged to the genus Thismia, whose other species were all native to places like Malaysia, New Guinea, and Borneo. Most of them had themselves only been discovered in the 30 years prior to Pfeiffer’s find.

Pfeiffer hadn’t just found the first Thismia species identified in North America but the only member of a decidedly tropical group in a temperate climate. No other species like it has been found since. “You can’t imagine a more significant discovery in botany,” Wilhelm says. “It would be a little bit like discovering a coconut tree quite wild and hardy living on the south side, on Blue Island Avenue or something.”

Nobody knows why tropical Thismia grew where it did. One Morton Arboretum botanist theorized that because the tract was within a few miles of the old stockyards, seeds from New Zealand might have come to town in the hooves of an imported sheep and somehow worked their way southeast. In perfect conditions, they might have sprouted and survived a few years–just long enough for Pfeiffer to spot them and watch them until they finally gave up trying to grow in 1916, the last year she saw the plant. “Of 450,000 plants [in the world], almost none of them have the capacity to be shipped around on sheep,” Wilhelm says. “Those that do have burrs, but this has tiny, minuscule seeds.”

Another bit of speculation botanists like to toss out just to shoot it down is that a bird or birds carried the seeds over. Birds wouldn’t be likely carriers, Wilhelm says, because “birds eat fleshy seeds–again, not the type of seed in Thismia.”

The most likely explanation is that there isn’t one, as Wilhelm sees it. “No one knows how original vegetations evolved,” he says. Thismia may have evolved here in response to the balmy years that followed the ice age 10,000 years ago, and then stuck around when the weather changed. “I suspect this is a relic, something that managed to survive from a far earlier time,” Wilhelm says. If he’s right, it must have started in some location other than the one where it was first identified (the “type location”), since that spot was underwater until 3,000 years ago. It can’t have done all of its evolution in that spot, he says, because “3,000 years is an eye blink in evolutionary time for it to be so distinct from its nearest relative.”

If Thismia survived at 119th and Torrence, it could also still be clinging to a piece of turf it grabbed millennia before that. But where, exactly? As Linda Masters, a botanist who works with Wilhelm, notes, “We’ve never found it in locations that are similar to the type location, but those are the only places we have looked. We’ve never looked for it in dissimilar places. We know so little about Thismia that we don’t know whether it was normally found where Norma saw it or in a completely different kind of setting.”

Looking for a needle in a haystack is bad enough, but it’s worse when you don’t even know which haystack to look in.

In a 1952 letter to a Field Museum scientist, Pfeiffer wrote that she visited Solvay every summer from 1913 to 1917, and saw Thismia each year through 1916. The next year, she wrote, “I hunted briefly but did not have adequate time for a thoroughgoing search. Since that time, I have often thought of searching similar locations as well as the original location. With enough time, I am sure I could locate it, if it is still in the region.”

Discovering Thismia was an amazing, life-changing experience, but not something Pfeiffer could turn into a career. Instead she built a distinguished professional record breeding lilies; over 49 years she published 65 articles in scientific journals. She gave her Thismia slides and a few specimens to the Field Museum. (The slides now stay locked in a cabinet with, of all things, the museum’s specimens of narcotic plants–peyote, coca, and the like.) Other specimens went to the Missouri Botanical Gardens in Saint Louis and the World Herbarium in Germany.

After a decade in North Dakota–during which she eventually became a full-time teacher with no housekeeping duties–Pfeiffer moved with her lifelong companion, Zella Colvin, to Yonkers, New York, to work as a research botanist at the Boyce Thompson Institute. The move must have been especially appealing to the woman scientist twice insulted by male rules: BTI was, for its day, heavy with women scientists. When the place was launched in the 1920s 7 of 23 staff scientists were female, says a retired administrator there. Pfeiffer stayed at BTI from 1924 until she retired in 1959. She died 30 years later at age 100.

While Pfeiffer was working on lilies, Thismia continued to captivate other scientists. In 1948 Floyd Swink of the Morton Arboretum obtained a detailed map of the original site from Pfeiffer and tried to find the plant; a colleague later lost the map. The same year, a botany teacher at Arkansas Agricultural and Mechanical College identified a tiny flower in the grass on campus as Thismia americana, which by then was listed in taxonomic guides to the United States. But word of the discovery didn’t reach Chicago until 1972, when the teacher mentioned it to a friend at the Field Museum. The chief of the Field’s botany department wrote to the college asking for help finding the plant, but got no reply.

In 1952 and 1956 Field botanists organized detailed searches of local prairies but came up dry both times. Thismia was relegated to legend status for a few decades, until Mayor Daley started floating the idea of building an airport on Lake Calumet. The airport boundaries included not only Thismia’s type location, but several other natural areas where scientists believed the plant could exist. George Johnson, a retired advertising executive and amateur botanist, organized the first Thismia Hunt in 1991 as a way to dramatize the devastation an airport would wreak on a part of the city that, amazingly, is one of Chicago’s best repositories of original species.

“We made the TV news with a bunch of botanists down on all fours in the prairies,” Johnson recalls. “It didn’t stop the mayor, but it helped make our point that anything that resembles the planet as it originally evolved or before white pioneers began agricultural and industrial development–there are so few fragments that have survived all that, we really can’t afford to give up any of them.” Johnson has organized the Thismia Hunt every year since 1991, but he admits that not one encouraging sign of Thismia has ever turned up.

Until this August, that is, when artist Paul Labus found a little white thing poking out of the ground on the Du Pont property. He called the professionals over to look, and “there was a lot of ‘wow’ and ‘oh my god’ going on,” the Nature Conservancy’s Crispin said later. “Everybody lay down on their bellies around it and took a good close look with our little nose lenses. We were all thinking botanical fame!” Which must be like movie fame, only nobody recognizes you on the street and you don’t make as much money.

When all the hunting parties regrouped at Gibson Woods Nature Center at 4 PM, Wilhelm and Masters were alerted to Labus’s find and quietly slipped out to examine it. A white-knuckled 45 minutes dragged by, near the end of which Johnson, one of the main keepers of the Thismia flame, glumly confided, “I can’t bring myself to say they’ve got it, or that we’ll ever find it. The whole idea is so remote, it’s unlikely.”

Finally, Wilhelm and his entourage arrived. Wilhelm announced that a Thismia impersonator had been found–it sure looked a lot like the real thing, he agreed, but it was only an odd offshoot of some plant’s root.

Labus, who had sat near the little impostor for an hour as his fellow hunters hiked back to the cars and drove to get Wilhelm, was still wound up when he finally got back to the nature center. Though it turned out he hadn’t rediscovered the weirdest plant in America, he was smiling and laughing giddily and devouring his chicken dinner. “I’m just an amateur, but I did keep looking, and all the associates Pfeiffer named were all there.”

Plant species have been known to reappear. As Masters noted in an academic paper, a species of lichen native near Cincinnati thought to be extinct since 1849 was found again in 1978 in southern Illinois, some 200 miles away. Ruddat says the dawn redwood only existed in fossil records until the turn of the century, when a group of living trees showed up in China. Their descendants are now sold in plant nurseries all over this country.

If the same thing happens with Thismia, all botanical hell will break loose. Tom Post, a regional ecologist for the Indiana Department of Natural Resources, explains that “in the plant world, there are collectors. Since Thismia is one of the rarest of the rare, there would be value to it, even pulled up out of the ground.”

Wilhelm points out that Thismia would immediately be a candidate for the endangered species list, “which would make it politically popular, aside from its scientific value.” Though the tiny plant isn’t flashy, its strange and reclusive life would surely romance the public.

On top of that, think of the stories you could tell. A tiny plant grows half a world away from where it ought to, then disappears a few years later, only to be found again after several decades. “If you found Thismia,” Post figures, “you could get on the Tonight Show.”

No, no, no, replies Wilhelm, ever the serious academic. “Thismia is good enough for Letterman.”

Art accompanying story in printed newspaper (not available in this archive): photos/Bruce Powell; illustration/courtesy the Field Museum.