“The flowers that are generally found with the leaves. In birches, they resemble long, conelike structures, dangling down from amid the leaves. Flower size varies dramatically, which would help narrow the scope. Better yet, would be a twig with bark. As you can guess from the names, black versus yellow versus paper, one of the key distinguishing features of birch is the color of the tree’s bark.”

“I only have a leaf,” Mac said, then muttered under his breath, “because our guy also likes a challenge.” He turned toward Kimberly, the tension building in his shoulders.

“He wouldn’t use something common,” she said quietly. “No compass, remember? So this time, the clues must narrow down a region. Or it’s really not that much of a game.”

“Good point.” Mac turned back toward the geographer. “You said birches are commonly found in Virginia. Are there any that aren’t common? Maybe a type that is rare or endangered?”

Ray’s dark eyes brightened. He stroked his chin. “Not a bad question… Nope, this isn’t going to help.” He flipped the book shut, seemed to think for a second, then turned abruptly to his computer and swiftly hit a bunch of keys. “See, what you guys really need is a dendrologist. I’m just a lowly geographer who’s spent some time dabbling with botany. A dendrologist, on the other hand…”

“Has a bigger name?” Kimberly asked.

“No, is a botanical expert on trees. See, I’m a generalist. Come on, ask me about a flower. I’m really good with flowers. Or ferns, for that matter. A dendrologist, on the other hand, could tell you anything you ever wanted to know about trees.”

“My God, there is an ologist for everything,” Kimberly muttered.

“You have no idea,” Mac said.

“See, you guys have come to the Richmond field office. Here, we’re mostly geographers and hydrologists. Most of us have other backgrounds as well-botany, biology, geology, etc., and we’re happy to help you out, but maybe we’re not as specific as you need. Now, up in Reston at our national headquarters, we got botanists, palynologists, geologists, karst geologists, you name it. That’s where the big dawgs live.”

“Where is Reston?” Mac asked.

“Two hours north of here.”

“I don’t have two hours.”

“Suit yourself.” Ray’s fingers danced over his keyboard. “Then for the time-conscious researcher, we have the greatest marvel of the twentieth century. Ta dah! The Internet, where for every ology, there is almost always a website. Let’s face it. Geeks love technology.” He hit return, and sure enough, a website of the U.S. Department of Agriculture labeled Dendrology of Virginia appeared on the screen.

“As I live and breathe,” Kimberly said.

“And how,” Mac seconded.

“And we have a final suspect for your consideration,” Ray announced. “Lady and gentleman, may I introduce Betula populifolia, otherwise known as gray birch. This smaller member of the birch family grows only thirty feet high, with leaves of approximately three inches in length. The bark may appear brown in color, but is in fact gray-white. It is also smooth, and not peeling, unlike the yellow birch and paper birch members of the family which, frankly, always look like they’re sporting a bad case of bed head. The wood is light and soft, used mostly for pulpwood spools and fuel. Better yet, it is located in only one area of the state. Huh, well, here’s the kicker. It doesn’t say where that is.”

Ray stopped, scrunching up his nose and wiggling it from side to side as he continued to study the screen. Mac hunkered down behind the geographer, his face taking on the intent expression Kimberly was coming to know so well.

“Are you saying this birch could be the one in our picture?”

“Could be.”

“And it’s found in only one spot in the entire state of Virginia?”

“That’s what the dendrologists say.”

“I need to know that spot.” Mac paused a heartbeat. “Now.”

“Mmm hmmm, mmm hmmm, mmm hmmm. Well, here’s a thought.” Ray tapped the computer screen with his pencil. “Look at the other ranges of distribution. The gray birch is common in New York, Pennsylvania, and New Jersey. All states north of us. Which means, this tree probably prefers cooler temperatures. So if it’s growing somewhere in Virginia…”

“The mountains,” Kimberly filled in.

He nodded. “Yeah. Now the question is, which range? Are we talking the Blue Ridge Mountains, the Shenandoah Mountains, the Appalachians? Hang on, I have an idea.” His chair shot across the room again. He found a directory on top of his bookcase, flipped through several pages, grabbed a phone and made a call. “Kathy Levine, please. She’s out? When do you expect her back? I’ll leave a message.” And in another moment, “Kath, hey, it’s Ray Lee Chee from USGS. Got a question about gray birch. Where is it in the state? It’s actually important, very Sherlock Holmes. When you get in, give me a buzz. We’ll be waiting. Bye.”

He hung up the phone, then met their expectant gazes. “Kathy’s the botanist with Shenandoah National Park. She’s more familiar with the trees in that area and if anyone knows about the gray birch, it’s her. Unfortunately, she’s out in the field right now.”

“For how long?” Mac demanded to know.

“Four days.”

“We don’t have four days!”

Ray held up a hand. “Yeah, yeah, yeah. Kind of got that. Give her until around noon. Come lunch, she’ll check messages, give me a call, and then I can give you a call. Noon’s only four hours away.”

“Four hours can be a long time,” Mac said grimly.

“What can I say? It’s not easy when you only have a picture of a leaf.”

“I have a question,” Kimberly spoke up. “From all of your various studies… Is there any connection between Virginia and Hawaii?”

“Virginia and Hawaii?”

“Yes.”

“Huh. Hell if I know. From a plant perspective, I can’t think of a thing. Hawaii’s kind of tropical, you know. And Virginia isn’t. Well, except for this week, of course. We’re always prepared to make an exception.”

“No other way they might be related?” Kimberly prodded.

Ray did the nose wiggle again. “You might ask a geologist. We have mountains, they have mountains. We have Chesapeake Bay with its multitude of barrier islands, which might be similar to their barrier islands. But from a flora and fauna perspective, I don’t see a relationship.”

“And where in this building might we find a geologist?”

“We don’t have geologists, you’d have to go to Reston. Wait!” He read her expression and immediately held up a hand. “I know, I know, you don’t have time for Reston. Okay… Jennifer York. She’s one of our core samplers, and I believe she has a background in geology.”

“Where’s her office?”

“Other side of the building, third office on the left.”

“Okay.” She turned toward Mac, who was looking at her with a puzzled expression. “You heard the man,” she said crisply, “let’s go find a geologist.”