59 
Anatomy of the Cohort Umbelliflorae. 
distribution of parenchyma in determining relationships seems not to have 
been realized. Because of this I have paid especial attention to the subject 
in my investigation. 
As stated above, the terminal connexions of the vessels of the Corna- 
ceae are generally scalariform, while those of the Araliaceae and of the 
Umbelliferae are characteristically simple elliptical or round pores. I have 
noted the condition of the terminal openings in my study, and have found 
results which corroborate the above statements. The condition of the 
terminal connexions between vessels is not as constant as is the distribution 
of parenchyma, but it may be mentioned here as worthy of notice. 
In recording my results I will first speak of the Cornaceae, it being 
usually considered to be the lowest family of the three. Among the genera 
of this family the commonest native genus is Cornus. PI. IV, Fig. i shows 
the type as illustrated in a transverse view of the species Cornns sanguinea. 
Here may be plainly seen the heavy-walled tracheides, the few small rays, 
and the numerous diffuse parenchyma cells. In PI. IV, Fig. % one may see 
a radial view of the same species, and the same features may be noted. The 
genus does not always show such heavy walls, nor is the parenchyma always 
as abundant. However, the relationship as regards the distribution of 
parenchyma and the character of the end walls of the vessels persists. 
In PI. IV, Fig. 3 we see a transverse view of the stem of Nyssa sylvatica. 
Here the parenchyma is plainly diffuse, and in other ways the wood closely 
resembles that of Cornus . Fig. 4 is a higher power of the same view 
as that shown by Fig. 3. Fig. 5 is a radial view of the same, and here we 
can see the even closer resemblance to Cornus , the parenchyma being more 
strikingly diffuse than in the transverse view. 
Here I would call attention to the fact that, under Engler and Gilg’s 
classification, Nyssa is placed outside the Cornaceae. Certainly the anato¬ 
mical structure would not appear to warrant this. 
Turning from our native forms to those exotic to this region, we find 
the parenchyma much less abundant. However, in Davidia involucrata 
(Fig. 6) one can plainly see the diffuse parenchyma and the scalariform 
vessels from the radial view. The number of bars in the vessel seems to be 
much more numerous than the number in the case of Cornus , but even 
among members of the same genus we find much deviation from the small 
number. Davidia is another genus placed by Engler and Gilg outside the 
Cornaceae. Clearly this would not seem possible when the internal anatomy 
is considered. 
In some exotic species the parenchyma appears to be entirely lacking. 
Its absence, however, is a common characteristic in plants living in a climate 
where the storage of food is not necessary. In most instances I was able to 
find remains of parenchyma cells, showing their persistent character. 
Fig- 7 is that of a radial section of the stem of Griselinia lucida. 
