136 ANATOMY OF STEM, ROOT AND LEAF 



(d) Elm {Ulmus campestris Sm. ). The fine vessels in the autumn-wood 

 appear arranged in many light coloured bands or lines more or less 

 parallel to the boundary of the annual ring (Fig. 66). The wood 

 of elm is darker than that of ash. 



(c) Spanish Chestnut {Casianea vulgaris Lam.). The fine vessels of 

 the autumn-wood are arranged in radial lines (Fig. 67), dis- 

 tinguished from oak, which it somewhat resembles in colour, by 

 absence of wide medullary rays. 



GROUP B. 



Annual rings with little or no difference between the spring and autumn 

 portion ; vessels scarcely, or not at all, visible to the naked eye. 



To this group belong : — 



Beech. Lime. 



Hornbeam. Willow. 



Sycamore. Poplar. 



I. Some of the medullary rays broad and readily visible to the naked eye, 

 the rest fine and only seen with a lens. 



[a] Beech {Fagus sylvatica L.). (Fig. 68.) 

 Wood reddish ; medullary rays with a 

 silky-shining lustre. 



(b) Hornbeam {Carpinus Betulus L.). 

 Wood yellowish - white ; medullary 

 rays dull and indistinct. 



2. All the medullary rays very narrow, but 

 appearing to the naked eye as very fine distinct 

 lines. 



(a) Sycamore {Acer Pseudo-platanus L.). 

 Wood hard, heavy, and white or pale 

 yellow in colour. 



(b) Lime {Tilia Sp.). Wood light, soft, 

 and reddish-white. 



Medullary rays quite invisible to the naked 



Fig. 68. — Transverse section 

 through annual rings of beech. 

 (Four times natural size.) 



3- 

 eye. 



{Salix caprea L.). Splint- 



[a] Willow 

 wood very pale red ; heart-wood deeper. 

 ((6) Poplars {Populus Sp.). Splint-wood white; heart- wood brownish. 



C. stems of Monocotyledons. 



In transverse sections through the stem of a monocotyledon, 

 a conspicuous difference is seen in the arrangement of the 



