platj: XXI.— cross sections. 



.4, PiNUS T.EDA, 'i*. r. rf., resin duct ; s. c, secreting cells; ni. )•., medullary rays; a, section of transverse tracheid of 

 ray ; b, the ray leaves the )>Iain of the section at this jioiut, small parts of it reappcarin;; further on ; e, simple 

 |iit» connectin-; parent liyiiia cells of the ray; d-e, part of a row of tracheids formed durin;; one season; 

 /, flattened terminal part of a traeheid. 



Ji, PiNlis lIKTKKoi'iiYi.i.A, '-'!". tp. ic., sprin);«'ooil ; •■<«. »■., sunimerwood ; a-h, part of a row of traelieids formed 

 during one season; e. teniiitial pails i>f Iraeheids; d. lioidered pit in sprinjjwood; e, same in sumiiuTwood; 

 other letters as in ./. 



C, Pixus GLABltA, J^". c, row of traelieids doubled; other letters as in li. 

 Originals, all ^V"- 

 144 



