PLATE 19 



Fig. 1. PhotoniicrogTapli of a portiou of a c-ioss-section of a six-year cili I 

 stem — sprciosus — sliowiii<; the afcuimilatioii of iiihlier in the rays and their wide 

 i-ortical exteiision.s. 



Fig. 2. Pliotograph of a portiou of a particularly thiu cross-section of a uiiie- 

 year-old stem — viridulu,^. 



(I. Tlie outer limits of the significant rubber-bearing coi'tex. 



[ 2<32 ] 



