APPENDIX IV 313 



red or yellow, whilst the Ehenacece are black or grey. The pith-rays are 

 numerous, fine, and equidistant ; but the characteristic features are the 

 somewhat irregularly concentric and wary, narrow bands of soft tissue, with 

 crowded small pores, and — still more so — ^the radial rows of moderately large 

 pores arranged in echelon between the pith-rays. 



The GuttifercB are another large Order of tropical trees, including that 

 yielding Gamboge, and having wood with that absence of rings so charac- 

 teristic of the tropics. Their timbers are usually reddish, with fine, but 

 clearly defined, pith-rays ; large pores irregularly distributed, singly or in 

 more or less radial groups ; and fine broken transverse lines of darker cells. 

 The genus CalopJiyllum, a species of which is represented in Plate XII., in- 

 cludes most kinds of Poon. 



Passing on to woods having distinct annual rings (Plates XIII. to XL.), 

 in which category are most of the broad-leaved trees of Temperate latitudes, 

 we find that they fall readily into the two groups known as " ring-porous " 

 and "diffuse-porous." The former (Plates XIII. to XXV,) have large or 

 numerous pores in the spring-wood, with smaller, fewer, or more scattered 

 ones in the summer-wood. They may be again subdivided (see pp. 45-49) 

 into those having the pores in the spring-wood larger than those in the summer- 

 wood, and those in which they are only more numerous and crowded. The 

 former sub-group includes Ashes, Locusts, Elms, Oaks, Hickories, Teak, 

 and Mahogany, etc. In the Ashes, one of which — Frdxinus americdna — ^is 

 represented in Plate XIII., the annual rings are defined by a very narrow 

 line of dense autumn-wood in contact with the conspicuous ring of large 

 pores in that formed in the succeeding spring. These large spring-pores are 

 oval, and form a loose ring of three to five rows, the pores diminishing radially. 

 The pores in the summer- wood are small, often two or three together, and 

 often coimected by soft tissue, forming short peripheral lines, as seen in the 

 upper half of the plate. The pith-rays are not distinct to the naked eye, or 

 even to a low-power lens : they are straight, except where they bend round 

 the large spring pores. 



Rohinia Pseudacdcia, commonly known as " Acacia " in England, and as 

 " Locust " in America (Plate XIV.), is a hard and heavy leguminous wood. 

 Its annual rings — in correlation, probably, with its deciduous character — are 

 weU defined by a Hne of dense autumn-wood, foUowed by an irregular " pore- 

 ring " of small, followed by larger, pores ; these latter being followed by 

 others gradually diminishing in size and number into the autumn-wood. 

 The pores are oval, solitary, or in radial groups of two to ten together, and 

 filled with thyloses, so that they appear as yellow-brown dots. The numerous 

 light-coloured pith -rays vary a good deal in width, and are very undulating, 

 bending to avoid the pores. 



The Laburnum, Cytisus Laburnum (Plate XV.), is another representative 

 of the deciduous Leguminosce of Temperate regions. Its wood is dense, often 

 very regularly concentric, the yellow sapwood contrasting markedly with the 

 dark-brown heart. The large irregularly formed pores in the spring-wood 

 are crowded together in crescentic groups of six to eight between the pith- 



