28 THE TRANSVERSE SECTIONS OF PETIOLES OF EUCALYPTS 



Outline of Section. — Generally oval and laterally expanded, sometimes roundish 



or angular, flatteced on upper and under surface. 

 Epidermis. — Thickness, ^^ — ^ in. 



Breadth, ^„ — ,4rn in., or half the thickness. 



' 1150 1500 ^ 



Cortical Cavities. — -^^ in. round, numbering from 7 to 2. 



Crystals. — Very fevp. 



Hard Bast.— Generally continuous, but irregular in thickness, giving it a zig-zag 



appearance. 

 Wood-curve (see Fig. 18). — Elongated, thickened at centre, with gentle 



inturning, and horns of medium length. 

 Vessels. — Largest, ^^ in. 



Average, about half that. 



Moderately numerous, vpide variations in size, lower portion of wood 

 comparatively free from them. 



Characteristic features : 



Section, — Flattened, about twice as broad as thick, tending to angularity. 

 Cortical Cavities. — Moderately large. 



Hard Bast.— Generally continuous, but irregular in thickness. 

 Wood-curve.— Slender, slightly thickened in centre, and short horns gently 



incurved. 

 Vessels. — Moderately large and numerous. 



9. E. tetraptera, Turczaninow ; four-winged-fruited Eucalypt. 



Shrub, seldom exceeding 10ft. in height. 

 Leaves.- — Very thick and equally green on both sides. 



Size of Section. — If line broad by 1^ thick, or nearly 1^ broader than thick. 

 Outline of Section. — Circular to oval. 

 Epidermis. — Thickness, ^^ in. 



Breadth, —^ in. or about \ thickness. 

 Cortical Cavities.^ — ^ in. round to oval, numbering from 4 to 2. 

 Crystals. — Numerous. 

 Hard Bast. — Continuous except where wood-curve is broken, and usually several 



cells thick. 

 Wood-curve (see Fig. 19). — Body thickened in middle, and gently incurved horns 



of medium size. 

 Vessels. — Largest, ^ in. and several ^ in. 

 Average, ^„ — ^ in. 

 Large, numerous, and distributed pretty regularly. 



