No. 454-] ANATOMY OF THE COM FERA 1 .ES. 699 



But it may assist in the general argunuMU to view this tiucstion 

 from another standpoint. Regardint;- the resin cells and the 



apply to the various forms of distribution and to the \ a nous 

 grades of resin reservoirs arbitrary values of such a nature as to 

 represent our conception of their relative positions in the st ale 

 of development as expressed by percentages, thus: 



Resin cells scattering - 5 o > 



zonate 37-5 " 



* " " grouped . . . ■ • 5 

 " " on the outer face of the inner wood, 



Pseudotsuga and Larix . • 12.5" 

 " on the outer face of the summer 



wood, as in Abies (partial only), 5-0 " 



" wholly wanting . ^-"^ " 



t Resin cysts, as in Tsuga, Abies and Seciiioia . /O.o - 

 Resin passages with constrictions, a> in l^eudo- 

 tsuga, Larix and Picea . ■ ■ • 

 Resin passages without constrictions and of the 



highest type of organization, as in I'inus . lOO.o 



We obviously have tw() subordinate series herc^which tor eon- 

 shown are "faulted" in such a way that the grouped le-m 1 1 i> ( ) 

 and the resin cysts (f) jointly represent the pomt ot diveigen^ . loi 

 two separate courses of development, the lattei conliiuriu^ up- 

 ward, while the former descend, and therein reiMe>enl> ^ie,:;ia- 

 dation. These features are best exhibited ■^''''''^""'J-' 

 accompanying curves clearly show how, on ^ c • ^ ij,^,^^;, ,^ 

 cysts and resin ])assages chKH'tlv result lioni ^pcua nvx 1 ua 

 of cell aggregates, while on the other hand, Ironi "^""^^ ^^^^ 

 ing point, there arises a course of degiadation ""^ ' - 

 results in the complete obliteration ot the re>m ce a^ an uu e- 

 pendent structure. 



The facts thus far set forth have thn.wn nnportant '^^'^Y'^";^ 

 the general course of development of certam anatomica ca m es 

 and they also show the general course of developn.ent lor genera 



