THE STRUCTURE AND DEVELOPMENT OF THE 
BARK IN THE SASSAFRAS. 
HowarRD FREDERICK WEISS. 
(WITH NINE FIGURES) 
THE common sassafras occupies a somewhat isolated position 
among northern trees. It is not only the single living representative 
of the genus Sassafras, but it belongs to the Lauraceae, a family with 
many arboreal genera in tropical and subtropical regions, but with very 
few in the cooler parts of the earth. The tree is further remarkable 
because its young branches remain green for a considerable period, 
differing in this respect from the majority of the trees among which it 
grows. For these various reasons it was hoped that a study of the 
bark might reveal features of interest. 
Métter has already studied the bark in several genera of the 
Lauraceae and has included in his published account a short descrip- 
tion of what he found in the sassafras.t According to his researches 
the family as a whole is characterized by the following peculiarities in 
the bark: a late appearance of cork; an epidermal origin of the phel- 
logen; a slight development of collenchyma in the outer cortex, most 
of the cells remaining thin-walled and parenchymatous; the occur- 
rence of stone-cells in the medullary rays between the strands of 
primary sclerenchyma; the presence of ethereal oil and slime in some 
of the parenchyma cells; the scattered bast fibers in the inner or second- 
ary bark. With regard to the sassafras in particular he notes that 
the cork is homogeneous and composed of thin-walled cells and that 
the inner bark is destitute of stone cells. It should be remarked that 
most of MOLLER’s material in this family consisted of dried bark, 
much of which was fragmentary and in poor condition. 
In his more general account of the Lauraceae SOLEREDER accepts 
the majority of M6LLER’s statements with regard to the bark.” Quot- 
ing from J. E. Wetss, however, he notes the fact that the phellogen is 
not invariably epidermal in origin, but that it is sometimes deriv ed 
t Anat. der Baumrinden 103-110. 1882. 
2 Syst. Anat. der Dicot. 795. 1899. 
Botanical Gazette, vol. 4r] [434 
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