PLATE I 



Fig. I. — A small lake near the junction of the east fork with the north 

 fork of the Kuskokwirp. A belt of horsetails, Eqitisctiiin, surrounds the edge 

 of the lake; outside this in the foreground is a belt of sedges, while the forest 

 of white spruce and paper birch appears on the right. July 9, 191 2. 



Fig. 2. — Niggerheads in the Yukon Valley near Tanana. These are 

 tussocks of tough grasses which grow higher from yea.T to year, often reaching 

 a height of two to three feet above the general level of the ground. Septem- 

 ber 12, 1911. 



