1884,] NATURAL SCIENCES OF PHILADELPHIA. 91 



BETULACE^. 



Alnus rubra Bong. Pyramid Harbor, Kaigan, Alaska. 

 A. viridis D. C. Harrisburg, Alaska. 



I have identified these with much hesitation, regretting on my 

 return home to find my material confined to a single branch of 

 each — the alders of Alaska being worthy, as I now believe, of 

 closer investigation. My botanizing at Harrisburg, and at Kai- 

 gan, had to be done beneath an umbrella and in pouring rain — 

 unfavorable for the close study of arborescent growth. If the 

 identifications are correct, the names would deserve to be trans- 

 posed. The " Harrisburg " species is the one prevalent from 

 there south through British Columbia to the Columbia River, 

 often making a tree I should judge from thirty to forty feet 

 high, and with a trunk occasionally say five to six feet in 

 circumference. The bark of the trunk is a dark reddish brown. 

 The finely serrulate leaves, however, seem precisely like the 

 leaves of A. viridis, as I have collected it on the mountains of 

 New Hampshire, and North Carolina, though it is difficult to 

 believe so small a shrub there, should be so fine a tree here. 



The alder of Kaigan and Pyramid Harbor is a much larger 

 tree, with a gray and rather smooth bark, even when quite aged. 

 At Pyramid Harbor, a summer settlement for salmon-fishing, 

 Indians had cut some down, and were making canoes — dug-outs— 

 of them. From memory I am sure some of these logs must have 

 been near three feet thick, and thirty feet long — the original 

 height of the tree being probably more than double this. These 

 were on rich bottom lands, near but not on the retreating 

 glacier's track. On the track the same plant apparently made a 

 dense shrubby growth, not taking on at all a tree-like character. 



Betula papyracea Ait. Chilcat Inlet, Alaska. 



Probably this species ; but the leaves seem all cordate and 

 densely woolly. Only a single tree was seen, not mature appar- 

 ently ; but there might have been more, for when found it was 

 approaching midnight and getting almost too dark for further 



explorations, 



SALICACEJE. 



Saliz Pallasii And. Bartlett Bay, Alaska. 



S. reticulata L. Bartlett Bay, Alaska. 



S. Sitchensis Sanson, var. denudata And. Bartlett Bay, Alaska. 



S. Barclay! And. Bartlett Bay, Alaska, 



