WRIGHT : THE GENUS DIOSPYROS 
the same age are connected by the intervening parenchy¬ 
matous medullary ray cell, and a fairly continuous circum¬ 
ferential circulation of food materials can therefore be 
effected through such elements. In a few cases, however, 
the tangential line of parenchyma only reaches half way 
from one ray, the terminal cell appearing in transverse section 
to be surrounded by unlike elements ; it is conceivable that 
there may be some connection in the vertical course. 
In the majority of our species the tangential lines of 
parenchyma are only one cell in radial thickness; in some 
species, notably D. affinis they are very often two, and are 
occasionally grouped in the middle of a patch of fibres. In 
some specimens of D. hirsuta the bands—two cells in radial 
thickness often run together through a vertical distance of 
over 0-8 mm. These tangential bands of wood parenchyma 
are separated from one another radially by patches «£ fibres 
from 006 to 0-18 mm. in thickness. These elements are 
the nwTi? 0Om “ mm0at,on like elements or those of 
fibrsTh th ^ 7 meam ° f their rad -l spaces, with 
fiy™ysnZ 8ential MriaC “- 3 “ d freeheal elements 
Theobliqne bands of wood parenchyma are obwions in 
material we*’ ^ •** * probable tbat if sufficient 
“ exammed -onld be found to occur in all 
if radial series, one slights^intemlTt ^ *” 
result in what may be a * he and th ” 8 
parenchyma. Adjacent cells are n “n 'I ®™® 4 By8tem ol 
another by a part of th^ir i- i Uy m Contact with one 
is therefore very srrad SUrfaCes> and the terracing 
connect one medullary ray tofhTLxfbT- ° £ parenchyma 
they tend to bring into dir~.t *’ b “ l U18 obTioa8 that 
tangential bands be^^l C ° m “' miCa,ion * he Missive 
therefore to establish? m/raT “T** ^ and 
between like elements in tissues of^different t 
