the »pigeon-holes» of the various herbaria, a task which must take years of work and long journeys. During the last 8 years the present author has tried to assemble and work up all this material, and it is his intention at last to get a flora of Alaska and Yukon in print. This paper may he regarded as an introduction to this flora.
        Even a very well known flora now and then yields additional data and further investigations will of course add a number ot' species to the Alaska-Yukon flora such as it is known today. The least known part is undoubtedly the mountains on the border between the Yukon and the Mackenzie districts. Doubtless a number of Rocky Mountain species not hitherto known to occur in our area will eventually be found there. The continuation of the Rocky Mts. north of Yukon River is also little known, but this district is so poor in species that not many new finds can be expected, although the distribution is very fragmentarily known in that part. The valley of Kuskokwim River, the region about Mt. St. Elias and Wrangell Mts., as well as the high mountains of the interior Seward Penins. are some of the less well known parts.
        Many of the high-alpine plants are known from too few stations to give any adequate view of their distribution, and it is very desirable that the high-alpine flora as a whole should be more extensively collected. The coastal belt will yield but few important additions.

List of collectors

The enumeration given below of botanical collectors who worked in Yukon and Alaska is chiefly based on a compilation of the statements found on the labels of herbarium sheets in various American and European herbaria as well as on information derived from literature. The chief herbarium with original collections from our area is the National Herbarium Washington, while others, viz. Gray Herbarium; New York Botanical Garden; National Herbarium, Ottawa; the herbaria of the University of California in Berkeley and California Academy of Science in San Francisco; Arnold Arboretum, Jamaica Plains; University of Washington, Seattle; Riksmuseum, Stockholm; and Botanisches Museum, Berlin-Dahlem, also own important Alaskan collections, which have all been considered in the list. Collectors who collected only one or very few specimens within our area are not enumerated in the list.
        Under the name of each collector are all scientific botanical