If you want to make your mark on the world of Yukon science, plants might be the field to choose. Botanically, the Yukon is still unexplored territory, says Bruce Bennett of the Canadian Wildlife Service in Whitehorse.

"Less is known about Yukon plants than is known about the birds, and very little is known about the birds."

Most of what is known about Yukon plants appears in a new book, Flora of the Yukon Territory, written by William J. Cody and published by the National Research Council Canada. Bennett already has his copy on order and plans to give it a permanent home in his backpack.

It's the first comprehensive guide to Yukon plants, he says. "Before this, we didn't even have a list of plants that occur in the Yukon."

However, Flora of the Yukon Territory is not the last word on Yukon plants. So far plants have been collected and identified mainly in easily accessible areas, or during reconnaissance for proposed protected areas, Bennett says. Others have been found by wandering botanists, both amateur and professional, but not as part of a comprehensive survey.

"If somebody didn't just happen to be walking by that place, this plant population might not be known," says Bennett. "That's why it's so easy to find a new species of plant for the territory right now."

Although he's been in the Yukon for less than two years, Bennett has already added a number of plant species to the Yukon list, including about 10 from the La Biche River valley alone. The species are known elsewhere, he explains, but they have not previously been reported in the Yukon.

"I always hope that maybe one day in the Yukon I'll find a species that's never been described before," he says. "The chances of that are pretty slim, but you never know."

One thing that keeps the hope alive is the large number of endemic plants in the Yukon region -- plants that occur nowhere else in the world. There are 32 species on the endemic list so far, some of them found only in the Yukon and some that extend into Alaska or the western Northwest Territories.

"Many of the endemics occur only in alpine areas now," says Bennett. "They survived in Beringia, an area that was not glaciated during the last ice age. This suggests they are things that remained isolated above the ice sheets and have since been restricted to mountaintops, or areas not recolonized by trees."

During the ice ages, when most of northern North America was covered with ice, parts of the Yukon were an open grassy plain. Some plants survived on that plain, while other populations of the same species survived south of the ice sheets. As a result, there are plants in the Yukon whose closest relatives grow thousands of kilometres away.

"Although the ice flow went away, they still haven't joined back up, so you have these pockets of plants that are quite distinct from each other," Bennett says. "They're almost to the point of being new species, but they're called disjunct populations."

Bennett, along with other scientists from the federal and territorial governments, is developing a rare plant tracking list, something that places like British Columbia and Alaska already have. It will help botanists determine where plants grow and whether they are threatened with extinction.

"We'll list candidate species and then co-ordinate that information with information already existing in Alaska and British Columbia," he says.

Compiling the list is a major undertaking. The Yukon has no existing list of plants and a limited botanical database. Many of the collections made in the territory must be sent to taxonomists in Ottawa for confirmation.

"We don't have the species inventory to look at plants the way we do with fish, birds, and mammals," says Bennett. The Yukon is home to about 1300 plant species, while approximately 250 bird species spend part of their lives here. In comparison, British Columbia has 2305 species of plants (only 14 of which are endemic) and approximately 298 birds.

For more information about Yukon plants, contact the Environment Canada's Canadian Wildlife Service in Whitehorse, 393-6700.