ANTHOPHTTA. 245 



460. The tissues of the Gymnosperms are individually 

 but little higher than those of the Fernworts, but in their 



Fio. 146.— Diagrammatic cross-sections of stems, showing the flbro-vas- 

 cular bundles, /c, of which x is the woody side and p the softer or barlt 

 side ; b, b, b, bast-flbres ; R, M, the fundamental tissues of the stem, of 

 which R (the rind) is the cortical and M, the medullary portion, or pith ; 

 ic, a belt of cambium which extends from bundle to bundle. 



arrangement they show great and 

 important differences. The fibro- 

 vascular bundles are of the col- 

 lateral form, and are so placed in 

 the stem that the harder and 

 more woody side is nearer the 

 centre of the stem, while the softer 

 side is always nearer to the surface 

 (Fig. 146, A). The inner part of 

 the bundles is composed mostly of 

 long, large cells, the tracheids, 

 which have the well-known char- 

 acteristic bordered pits (Fig. 147). 

 The outer part contains, besides 

 other tissues, a little fibrous tissue 

 (bast-fibres). Between these two 

 halves of the bundles there is a 

 thin layer of growing cells (cam- 

 bium) which is continuous with a layer between the bundles 

 (Fig. 146, A and £). At this stage the stem is composed 



Fig. lit. — Longitudinal 

 section of wood of a Pine 

 (Pinussylvestris). Bordered 

 pits, t',t',t" ; a-e, parts of six 

 tracheids ; st, large pits, 

 where medullary rays touch 

 tracheids. Magnified 335 

 times. 



