Anatomy of the Cohort Umbelliflorae. 57 
Among the members of the Cornaceae, Mastixia stands out as peculiar. 
I have already mentioned the peculiarity in regard to the secondary hard 
bast, and in regard also to the presence of cortical bundles. There is yet 
another peculiarity which is found in no other place in this family, but which 
is characteristic of the two higher families. This is the presence of secretory 
canals in the cortex and in the pith. The presence of these canals has 
caused much discussion concerning the true relationship of this genus. 
Baillon (6) placed it with the Araliaceae next in kin to the genus Anthro- 
phyllum .. Later, he reconsidered and changed his opinion. Van Tieghem (8) 
came, through his work, to the view that it belonged neither to the Corna¬ 
ceae nor to the Araliaceae, but rather to the Dipterocarpeae. Later, he also 
changed his opinion. Burck (9) also came to the view that it stands very 
near to the Dipterocarpeae, though the Simarubeae and the Liquidambeae 
must also be taken into the reckoning. 
Though the above opinions show that Mastixia is a much-discussed 
genus, and that its position is rather unsettled, yet the other characteristics 
would seem to indicate that it belongs to the Cornaceae, and here it is 
generally" placed. Granting that Mastixia is one of the Cornaceae, it is 
argued that it must serve as a connecting link between that family and the 
Araliaceae. The basis for this argument is chiefly the presence of secretory 
canals in pith and in cortex. Such canals are a constant feature in the 
Araliaceae and in the Umbelliferae. In answer to the above argument 
it can simply be said that the presence here of secretory canals does not 
seem to be conclusive evidence, in this case, of a close relationship. We find 
in the family Hamamelideae that only the Altingeae, with Liquidambar as 
our common example, are characterized by internal secretory canals. 
Secretory canals also occur in some members of other families, while they 
are lacking in other members of the same family. Here, evidently, their 
presence or absence does not change their relationship. Only in such 
families as the Araliaceae and the Umbelliferae, where they are present 
in every member, are they evidence of close relationship. In the Cornaceae, 
they are found only in Mastixia. Hence they are not characteristic of the 
family, and would not seem to me to be of great value in showing relation¬ 
ship where that family is concerned. 
Having now spoken of the more important and noticeable anatomical 
features of the Cornaceae, let us turn briefly to the like features in the 
Araliaceae and in the Umbelliferae. 
In the Araliaceae secretory canals are present throughout the entire 
family, being present in all parts of the cortex and often also in the pith. 
Another peculiarity found nowhere among the Cornaceae is the presence of 
medullary bundles. These are formed in a ring, having collateral structure, 
and being inversely orientated so that the xylem is towards the outside. 
I have noticed these in the petiole of Aralia chinensis var. manchuria , 
