85 



known is that contained in the large tamarack swamp near Mineral 

 Springs in Porter C'ounty. In this swamp arc found tamarack and 

 white cedar. It was in this swamp that the writer found a peculiar 

 form of birch which has been determined as Betula Sandhergi. Since 

 this species' is recognized as a hybrid of Betula papyrifera and Betula 

 [nun /la vai'iety glaiKtuIifcra, and the last parent of this hybrid is not 

 found in the vicinity, a dis(^ussion of this form is not pi'esented. In 

 the immediate vicinity arc fouml only Betula lutea and Betula puniila. 

 Betula papyrifera is found about a mile distant to the south. It is 

 assumed that this form is a cross Ijetween/^e/f/^a lutea and Betuln pumila. 



2. Botula popiilifolia INIarshall. Gray or White BircIi. Plate 



33. A small tree; bark a chalky white, not separating into thin layers, 

 inner l.)ark orange, on the trunks of old tiees nearly' black; shoots at 

 first covered with numerous glands, becoming smooth and yellowish 

 or reddish-brown; leaves generally long-deltoid, average blades 3-0 cm. 

 long, usually long taper-pointed, truncate or nearly so at the base, 

 irregularly doid)le-scrrate, slightly pubescent on the veins when young, 

 soon becoming glabrous; fertile catkins 1.5-3 cm. long and about 7 

 mm. in diameter; bracts of eastern trees differ from those of Indiana 

 trees which are about 3-4 mm. long, lobed to about 1/3 of the distance 

 from the apex, lateral lobes the largest and strongly divaricate, puber- 

 ulent on the back; seed strongly notched at the apex; nut slightly obo- 

 void; wmgs mucdi broatler than the nut. 



Dislribiilioii. — Nova Scotia west to southern Ontario and south to 

 Delaware and Pennsylvania. In Indiana it has been reported from 

 Lake, Laporte, Porter, St. .Joseph and Tippecanoe Counties. Theie 

 may be some doubt about the Tippecanoe record, since many of the 

 older records were made from cultivated trees. The numbers of the 

 species in Indiana, were always limited. It is not able to meet changed 

 conditions and it has already almost disappeared from our area. I 

 was told that formei'ly this species was found all about a lake in Laporte 

 County, but it has all tlied out. Its appearance in Indiana is peculiar 

 since it is not found west of us, or north in Michigan or cast in Ohio. 

 This small group of trees near Lake Michigan is three or four hundred 

 miles from the nearest of their kind. 



Keiiiarlvs. — This species is called white and gray birch. The 

 largest ti'ee seen in Indiana was aJiout 2 dm. in iliameter and 13 ni. high. 



3. Betula papyrifera Marshall. P.vper or Canoe Birch. Plate 



34. Pather a small tree ; l)ark thin, creamy white ; chalky, dark near the 

 base on olil trees, separating in thin pajiery layers; shoots green, glandu- 

 lar and hairy, becoming glabrous aiul reddish-brown; leaves ovate or 

 rhombic-ovate, acute to long tapei--pi)inted, truncate, rounded or 



, Minnesota Bot. SIndios 4:4.54:191(1. 



