THE LABUENUM 21 



almost continuous ring, so that the wood is classed as 

 " ring-porous.'' The vessels formed later in the year 

 make crescentic groups, producing the effect of a series 

 of undulating lines also nearly continuous round the 

 stem. In the denser, more opaque portion, a more 

 minute study would reveal tracheids, differing from 

 the vessels mainly in their lesser diameter and length, 

 wood-fibre and cellular tissue. It is these elongated 

 but dense elements of its structure that render the 

 wood at once So flexible as to be suitable for bows, and 

 so hard as to be used as a veneer in cabinet work. 



The tree does not branch very copiously, as many 

 of its small side buds give rise to short dwarf-shoots 

 marked with closely-ranged ring-scars of the bud- 

 scales. Leaves and flowers appear simultaneously in 

 May, the former being grouped together in tufts. 

 The leaf-stalks are long, and each of the three ellip- 

 tical leaflets is furnished with a minute stalk or 

 petiolule. The ceiitral leaflet has a slight joint or 

 articulation at its base which indicates that this com- 

 pound leaf, unlike that of the Clover, belongs to the 

 pinnate type. Two small persistent stipules occur at 

 the base of the leaf-stalk, and the young shoots and 

 the under surfaces of the young leaves are alike covered 

 with a silvery coating of flat silky hairs. 



Digging near the roots of old Laburnum trees, we 

 shall probably come across curious coral-like masses 

 of tubercles which we shall find to be attached to 

 the roots, and which we might well take for galls. 

 These "exostoses," as they are termed, occur on almost 

 every member of the Order Leguminosm ; but are 

 particularly large on the Laburnum, the clusters in 



