I0 4 BOTANICAL GAZETTE. [April, 



tents of the cells, and they are classed among the resin se- 

 creting cells because of their similarity in structure and ar- 

 rangement to the typical resin ducts, and the close relation- 

 ship ot laxodium to resin secreting plants. 



The resin duct of Taxodium, when compared with the 

 secretory system of Pinus sylvestris, appears remarkably 

 rudimentary. Leaving out of view the greater number of 

 ducts found in Pinus, a comparison of the duct of Taxodium 

 with a single duct of Pinus conhrms us in the thought that 

 we have in the former the beginnings of a system, which is 

 fully and strikingly developed in the latter. In Pinus we 

 find in transverse section the almost perfectlv circular outline 

 a 11 S?\ G scl f rench ymatous investing "ring at times of 

 double thickness, the more numerous and regular secretory 

 cells often of more than one layer, evidencing in every case 

 a complete differentiation from the surrounding tissues, and 

 an apparently perfected system. 



In Taxodium, on the contrary, the whole duct gives evi- 

 dence of an incomplete differentiation. It agrSes more 

 nearly in every particular with the duct of Pinus sylvestris as 

 ound at the commencement of its development in" the young 

 leaf (cf. figs, ii and 12). . to 



In this system, then, as well as in the cases of the stomata 



'■« -a gt f ning Cdl S ^ Stem ' the leaf of Taxodium 

 fhTJ Pi„?- Ce a mUCh lGSS com P lete development than 



The fibro-vascular bundle 14 



that of Pinus. 



///. Ft 



*v,n~ 4-u — i — V 'J-™*""* — iIA c nuiu-vascuiar Dunaie 1 "* 



follows the general rule which obtains among the Conifer* 

 in having a separate course and free end, and also accords 

 with the condition, so tar as it has been invesiigated, among 



1 n£ P T 1 ^ le * , ' n l bein g sin g ] e and median. While thS 

 Si ch 1S of the collateral type, in transverse section, 



„ If ? Ce ' ***** * •*»<! out sharply and distinctly, it is 

 belno t "°r f lftC 1 Ulty \° aSsi ^ n to ^ ■ definite limit? there 

 the snrrn! n^- f- hCath and . the P a ™chymatous elements of 



wkhi tZu m % tlS - ue ?/ as «"g gradually into those which lie 

 within the bundle itself. The nripnt.ti^ ~r *u~ v..-ji- :«, 



The orientation of the bundle is 



shZlv Tl V hG en 1 ■' 1S ta P ered s °mewhat, though not 



inS; H lhe -Y lem '^h^h is irregularly semi-crescentic 



face until ^ n, i eS /- S * CX . tends t0ward tne "PP^r leaf sur- 



rachelde "i* 1 ™** «»■*■ of but two or three rows of 



tmc^d^^h^Jio^ve^^ contact with 



and Ferns, 300. 8 eim 8 Jailrt> - IV -> 43 > Cf. also, de Bary, Comp. Anat. of Phan. 



