cm 



cl Old World Birches. 179 



mens are practically identical with Rosenvinge's Kos. 174 and 

 210 from Greenland. This shrub or dwarf tree offers consid- 

 erable variation in the outline and toothing of its leaves, but 

 no more than does the same form abroad ; and since the young 

 branchlets and leaves are sometimes pubescent as in B. alba 

 its treatment as a dwarf variety seems the wiser course, and 

 the shrub may be known as Betvia alba, var. minor (Tucker- 

 man). 



Betula alba, var. carpatica. 



A shrub growing on Anticosti Island at the mouth of the 

 St. Lawrence {Macoun in Herb. Geol. Surv. Can., No. 23,823) 

 differs somewhat markedly from other American forms. It is 

 nearest Betula alba^ var. minor, but differs in its broadly 

 rhombic leaves, mostly cuneate at base and permanently pubes- 

 cent beneath, especially on the nerves. This shrub is undoubt- 

 edly the B. borealis, Spach* (B. joicmila, y bo7'ealis, Kegel, 

 Mon. Bet. 55, t. 13, figs. 38, 39), described from Newfound- 

 land, and it is identified with Kegel's descri^Dtion of B. pubes- 

 cens, ^ carpatica\ {B. carpatica, TTaldst. and Kit. in Willd. 

 Sp. iv, 464). The specimens, except in their more abundant 

 pubescence (in this matching Kegel's " folia subtus in venarum 

 axillis saepe barbata "), are well matched by a Lapland sheet 

 distributed by Kegel as B. pitbescens, var. carpatica ; and they 

 are equally well matched by a sheet distributed by Fries as 

 B. glutinosa. This plant, B. glutinosa of Fries, not Wallroth, 

 is treated by Guerke as identical with B. carpatica. The 

 same form is well represented in Flora Danica (xvi, t. 2851) as 

 B. odorata, var. rhombifolia, Lange, with B. odorata, var. 

 carpatica, Lange {B. carpatica, Waldst. and Kit.) cited as a 

 synonym. Guerke, however, does not identify B. rhombifolia, 

 Tausch, with B. carpatica, and considering this doubt it is 

 least confusing to call the plant Betula alba var. carpatica 

 (Waldst. and Kit.). The same form occurs in the Herbarium 

 of the Canadian Geological Survey from Banff, Alberta [San- 

 son, Nos. 22,298 and 22,444), though in its somewhat resin- 

 iferous branchlets the first cited specimen tends toward B. 

 wdcropJiylla, Bunge. An old specimen collected by Dr. Kich- 

 ardson on the Franklin Expedition (sheet No. 23,628, Herb. 

 Geol. Surv. Can.) is apparently the same. 



Betula pendula. 



Betula pendula, var. japonica. 



Aside from Betida papyrifera and B. occidentalis the only 

 birch of the section Albae generally recognized in America 

 until within three years has been B. populifolia, a purely 



* Spach, Ann. Sci. Nat., ser. 3, xv, 196 (1841). f Eegel in DC, 1. c. 168. 



