PINACEiE 279 



Compression, crushing strength with the grain, 3,480 lb. per 

 sq. in. 



Shearing, strength with the grain, 860 lb. per sq. in. 



Bending, modulus of elasticity (stiffness), 1,240,000 lb. per 

 sq. in. 



Hardness, weight required to half-imbed a 0-444 in. steel baU, 

 390 lb. per sq. in. 



The bark has medicinal properties, its action being alterative, 

 diuretic, and laxative. It is recommended in cases of jaundice, 

 obstructions of the liver, rheumatism, cutaneous disorders, etc.^ 



L. americana in a natural state ^ occupies both wet and dry 

 soils, the best trees being found upon rich and light upland soils, 

 whilst large numbers of smaller trees occur on wetter and heavier 

 land. In swamps where water covers the surface of the soil, 

 the tree only just manages to exist. In places subject to decided 

 drought it is a failure. It is most plentiful in the swamps and 

 silted lake-beds of northern regions, where it occurs in dense, 

 extensive pure stands or with arbor- vitse and black spruce. 

 Being intolerant of shade, it must be able to dominate other 

 species in mixed stands. The value of this larch in N. America 

 lies in its ability to succeed under conditions unfavourable to 

 other trees. In Britain it is occasionally seen in old collections 

 of conifers, but has been neglected by modern planters and is 

 seldom obtainable from English nurseries. It is less successful 

 than other species, and can have Uttle or no value as a commercial 

 tree in Britain, though it might be useful as a first covering for 

 wet, exposed land at a high altitude. 



Larix Cajanderi, Mayr. 

 Cajander's Larch. 

 We do not know this species, but according to Elwes and 

 Henry^ it was discovered by Dr. Cajander in E. Siberia, where it 

 occurs along the banks of the river Lena from the mouth of the 

 Aldan at 68° N. lat. northwards to 72° N. lat., becoming here a 

 stunted tree only 10-12 ft. high. It usually forms mixed woods 

 with the Siberian spruce or with Betula odorata, assuming in wet 

 soil a stunted habit ; on unflooded land growing pure to a height 

 of about 70 ft. Judging from the description, it is closely aUied 

 to, if not a variety of, L. dahurica. Young branchlets yellowish 

 brown with scattered hairs, older branchlets becoming ashy grey. 

 Leaves up to 2 in. long, showing when the bud opens a tuft of 

 dense whitish pubescence which is absent in L. dahurica. Cones 

 small, of about 20 scales, which gape widely when ripe and are 

 broad and concave on the upper margin. 



1 Potter's Cyclop, of Bot. Drug Prep., 278 (1915). 



2 Forest Service Circ. U.S.A. Dept. Agric, No. 89. 

 ^ Elwes and Henry, loc. cit. ii, p. 346 (1907). 



