180 Fernald — Relationships of some American 



American species quickly distinguished by its comparatively 

 low stature and southern range, its chalky white or gray-ilecked 

 close and scarcely defoliating bark, its glossy extremely cau- 

 date-attenuate deltoid leaves, its compact grayish brown fruit- 

 ing strobiles averaging S^"" long and 6™™ thick, and the samara 

 rarely S'S"""" broad. Yery recently, however, three trees have 

 been described from northwestern America as unique American 

 species: Betula Icenaica, W. H. Evans,* from Alaska; B. 

 alasl^ana^ Sargent,f from Saskatchewan and Alaska ; and B, 

 fontinalis^ Sargent,! the Ro(?ky Mountain half-shrub which has 

 there passed as B. occidentalis. 



The writer has not seen the original material of B. henaioay 

 but a large suite of specimens collected by Messrs. Coville and 

 Kearney in the type region, on the Harriman Alaska Expedi- 

 tion, has been placed in his hands by Mr. Coville. This series 

 of 15 sheets in the United States S^ational Herbarium is sup- 

 plemented by very important notes by Mr. Coville on the color 

 of the bark, etc. 



The first specimens cited by Professor Sargent for his Betula 

 alasTcana are one of Bourgeau's collected on the Saskatchewan 

 during the Palliser Expedition, and Macomi'S material from 

 Prince Albert, Saskatchewan, collected in July, 1896 (not 1876 

 as originally published). The other material came from Alaska 

 and the tree is said to be " the ' canoe birch ' of all travellers 

 in Alaska, and it is the common birch tree of the Yukon 

 Yalley." The Bourgeau plant, the first specimen cited by 

 Professor Sargent and consequently (for want of any speciall}^ 

 indicated specimen) to be regarded as the type, is in the Gray 

 Herbarium. This plant was labelled by Pegel and was 

 included by him in the Prodromus as B. alba, subsp. verrucosa 

 8 resinifera, a form otherwise known to him from Amur, near 

 Udskoi (latitude 55°) on the Okhotsk Sea, and from the neigh- 

 boring province, Transbaikalia. B. verrucosa, var. resinifera 

 was distinguished by Kegel from the typical B. verrucosa by 

 the densely resiniferous branchlets, a character very conspicu- 

 ous in the Bourgeau specimen, but less marked in Macoun's 

 Saskatchewan material. And although in B. henaica the 

 twigs were originally described as " not resin-dotted," later 

 collections show the character to be inconstant and that the 

 twigs are sometimes quite as glandular or resiniferous as in the 

 Bourgeau specimen of A. alashana ; and furthermore, B. alas- 

 Tcana has the twigs only " more or less verrucose with conspic- 

 uous resinous glands," so that little stress should be laid upon 

 this character. 



A comparison of th6 original descriptions of Betula henaica 

 and B. alasTtana shows no point by which they can be sep- 



* Bot. Gaz. xxvii, 481 (1899). f Bot. Gaz. xxxi, 236, 239 (1901). 



