In the summer of 1899, American botanist John Berry Tarleton spent months travelling from Skagway to Dawson. While late gold seekers sped past him, Tarleton poked along the banks of the Upper Yukon River, looking for plants. And he found his own kind of treasure.
In the plant collection he sent to the New York Botanical Gardens were six species new to science. The collection also contained the first Canadian example of a plant found only in Alaska until then – the spiked saxifrage, or Saxifraga spicata.
It was 110 years before the next sample showed up.
Bruce Bennett, wildlife viewing biologist with Yukon Environment, says he’s surprised it took so long to find another example of spiked saxifrage. The spiked saxifrage is hard to overlook. It’s a large plant, with wide, saw-edged leaves
clustered around its base. The stalk that towers above the cluster of leaves can be 60 centimetres tall or more. It carries a few smaller leaves and the flowers, cream-coloured and about a centimetre across.
“It’s huge. It’s beautiful. I can’t understand why people haven’t found it before,” says Bennett.
So, when Stu Withers and Grant Lortie of Laberge Environmental Services were planning some fieldwork in the Dawson area, Bennett gave them a shopping list of plants to watch for. Spiked saxifrage was on the list, and, like Tarleton before
them, they hit the jackpot.
On July 15, 2009, they found spiked saxifrage growing along Donahue Creek near where it flows into the Yukon River. That’s 95 kilometres upriver from the spot where Tarleton found his plant, near where the Indian River joins the Yukon. It’s a
full 430 kilometres, as the river flows, from the next known current stand of saxifrage in Alaska’s Yukon and Charley Rivers National Park & Reserve. That makes it the most easterly specimen found so far.
The site where the plants were found is remote, over 100 kilometres from the nearest road and most easily reached by river. There were fewer than 100 plants growing on the stream bank. Withers collected a couple of them as samples to take
back to Bennett.
Spiked saxifrage is a relic of Beringia, the ice-free zone that stretched from the Yukon through Alaska and across the then-dry Bering Strait to Siberia during the last glaciations. It’s a Beringian endemic, a plant that is found only in Alaska and
the Yukon. Bennett says it’s most common in moist, shady locations such as riverbanks overgrown with alders. The Yukon is the edge of the spiked saxifrage’s range.
“I think it got too dry here,” he says.
The first botanist to collect the spiked saxifrage was David Nelson, a botanist sailing with Captain Cook in his 1778 survey of the northwest coast of North America. He found it on Sledge Island, near Nome in western Alaska. Since then, the
plant has been found at many locations in Alaska mainly in river drainages, but also occasionally on the tundra.
That first collection point, Sledge Island, might be near the western limit of the plant’s range. Many Beringian species are found on both sides of the Bering Strait since, during the Beringian period, dry land connected Alaska and Siberia.
However, so far, the plant hasn’t been identified in Siberia. Bennett says it might be there, still unreported or Siberia might have similar, closely related saxifrage species.
The specimens collected last summer by Withers are not the first collected in Canada, but they will be the first to stay in Canada. John Berry Tarleton’s collection went to the New York Botanical Gardens, where it still resides.
“There isn’t a Canadian specimen in any Canadian herbarium,” says Bennett.
Now that will change. One of Withers’ specimens will be sent to Ottawa where Agriculture and Agrifood Canada maintains the tenth-biggest herbarium in North America and the largest in Canada. It contains the most extensive collection of
Yukon plants.
The other specimen will remain in the Yukon, in Bruce Bennett’s private herbarium. Bennett has been collecting Yukon plant specimens for several years. He now has almost 7,000 specimens, which makes his the second-largest collection in
Canada. The complete collection has been entered in a database and can be searched online at www.pnwherbaria.org.
Meanwhile, he hasn’t given up hope of more sightings of spiked saxifrage in the Yukon. In Alaska, it’s uncommon but not particularly rare. Patches of plants have been found at scores of locations, mainly along the Yukon River drainage.
Bennett suspects there are more patches of the showy plant in the Yukon, possibly in hard-to-access locations like the Donahue Creek site.
If you think you’ve spotted another stand of spiked saxifrage, or any other unusual species, contact Randi Mulder of the Yukon Conservation Data Centre at randi.mulder@gov.yk.ca.
For information about Yukon wild plants, contact Bruce Bennett at bruce.bennett@gov.yk.ca.
This column is co-ordinated by the Northern Research Institute at Yukon College with financial support from Environment Yukon and Yukon College. The articles are archived at www.taiga.net/yourYukon.