462 



separated by 1 tu 4 raws of ftbre-tracheids often adjoining 

 vessels. The cells of the l-seriate rays resembling those 

 of the l-seriate stories. 



Description of the éléments. 



I. Vessels. R. 25 to 80 /<, T. 20 to 70 /<. Elliptical 

 and circulai' cylinders or multilatéral prisms with rounded 

 edges. Transverse walls placed very obliquely, showing 

 scalariform perforations with 50 to 125 horizontal rungs. 

 The scalariformly perforated part of the transverse walls 

 sometimes 500 /< in length. Walls 1.5 /< thick; — with 

 numerous transversely elongated bordered pits, wben 

 adjoining each other; — with very numerous elongated 

 bordered pits, when adjoining fibre-tracheids; — with a 

 few simple and numerous elongated onesided bordered 

 pits, when adjoining wood parenchyma cells and upright 

 ray-cells; — with unilatéral bordered pits, when adjoining 

 procum.bent ray-cells. 



II. Fibre-tracheids. R. 20 to 30 fi, T. 25 to 35 /*; 4- to 

 8-angular. Walls thick 6 to 8 ^m; — with numerous elon- 

 gated bordered pits, when adjoining vessels or each other; 

 thèse pits more numerous on the tangential than on the 

 radial walls; borders of pit-chambers circular or somewhat 

 elongated in a vertical direction, e. g. 5 by 6 /n. 



III. Wood parenchyma cells. Those adjoining vessels 

 mostly elongated in the direction of the circumference of the 

 vessels. Walls thick 1.5 ^ ; — with a few simple, and numer- 

 ous elongated 1-lateral bordered pits, when adjoining vessels ; 

 — with elongated 1-lateral bordered pits, when adjoining 

 fibre-tracheids; — with simple pits when adjoining each 

 other or ray cells. Contents: sometimes a few starch 

 grains and some red brown mass on the transverse walls. 



IV. Cells of medullary rays. Walls thick 1.5 /« or more: 

 pits the same as in the wood parenchyma cells. 



