THE ANATOMY OF WOODY PLANTS 



in C. Fraseri, but the large band of radial parenchyma is obviously 

 not homogeneously parenchymatous, but is separated into pointed 

 groups by the presence of interspersed fibers. In other words, 

 instead of a continuous mass of storage tissue there is present 

 an aggregation of rays of a certain size, separated from one another 

 by strands of fibers. This condition of the large ray may be 

 conveniently designated as aggregate. In Fig. 60 is represented 



the tangential 

 aspect of the wood 

 in C. equisetifolia. 

 In this type we no 

 longer see a sharp 

 contrast between 

 large multiseriate 

 or aggregate rays 

 and small entirely 

 uniseriate ones, but, 

 as it were, a more 

 democratic organi- 

 zation of the radial 

 parenchyma, in 

 which no extremely 

 large radial paren- 

 chymatous masses 

 are found, as all 

 grade almost imper- 

 ceptibly into one another in size. The last-described condition 

 of the rays, for reasons to be indicated later, is here designated 

 as diffuse. We have thus in the single genus Casuarina three 

 distinct types of radial parenchyma: first, the northern oak type 

 in which huge rays stand in the sharpest contrast to narrow uni- 

 seriate bands; secondly, a condition in which the contrast still 

 obtains as regards the dimensions of the rays, with the dis- 

 tinction that the large masses are not homogeneous but pene- 

 trated by bands of fibers; and, finally, there is to be noted a state 

 or organization in which all rays are of moderate width and are 

 scattered somewhat evenly throughout the tangential or transverse 



FIG. 58. Tangential section of the wood of 

 Casuarina Fraseri. Explanation in the text. 



