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writer, and the present reference of our specimens is based on an iden- 

 tification by Herr Rittmeister von Seemen of the Berlin Herbarium. 

 Our Yukon Valley specimens are as follows : 



Forty7nile Creek. — Near the junction of Fortymile Creek ^vith the 

 Yukon River, Frederick Funston, 1893 (^o* 42a). 



Dawson. — "Island near footbridge," R. ^. Williams, 1899. 

 Fifty mile River. — Collected by Arthur L. Bolton, 1899. 

 Salix arbusculoides most resembles, among Alaskan willows, Salix 

 sitchejtsis., but the toothing and less distinctly oblanceolate character 

 of the leaves, the lack of the permanent satiny 

 lustre of the lower leaf surface, and the presence of 

 two stamens instead of a single stamen in the male 

 flowers, distinguish arbusculoides. Salix sericea 

 Marsh., of the eastern United States, is another 

 species resembling arbusculoides but its leaves 

 are slightly hairy on the upper surface, at least on 

 the midrib, and the apex is acuminate, while the 

 catkins are more densely flowered than those of 

 arbusculoides^ with the scales usually black, and 

 ]-ather densely villous. In arbusculoides the leaves 

 are entirely smooth above, even to the midrib, and 

 the apex is merely acute, the point sometimes 

 blunt ; and the catkins are more loosely flowered, 

 he scales light to dark brown, scarcely black, 

 sparingly villous. The willow described by von 

 Seemen in 1895 as Salix saskatchavajta^ SQems 

 to be closely related to Salix arbusculoides but 

 the statement regarding the leaves, " untere Seite 

 in der Jugend fein seidig behaart, im ausgewach- 

 senen Zustande beide Seiten kahl.^" furnishes the 

 presumption of a specific distinction. 



In addition to the flowering specimens collected 

 by Air. Funston mature leaves and fruit were 

 collected at Dawson, Yukon Territory, June 19, 1899, by Mr. R. S. 

 Williams, and similar mature specimens at Fiftymile River, Yukon 

 Territory, in the same year, by Mr. Arthur L. Bolton. From the upper 

 Yukon the species extends eastward nearly or quite across the northern 

 part of the continent. None of these collectors described the habit of 

 the plant, but it certainly is not a prostrate species, and doubtless is 

 not a tree. 



Fig. 21. 

 arbusculoides 

 ders. : <?, pistillate 

 flowering twig, 

 natural size ; b, 

 pistillate flower, en- 

 1 a r g e d six dia- 

 meters; c, scale, 

 same enlargement ; 

 d, mature leaf, 

 natural size. 



' Seemen, Engl. Bot. Jahrb. Beibl. 52 : 7. 1895. 



