HISTOLOGY OF PHLOEM IN WOODY ANGIOSPERMS 
Table i — Continued 
369 
Oleaceae 
Fraxinus americana 
Fraxinus nigra . 
Bignoniaceae 
Catalpa bignonioides 
Rubiaceae 
Cephalanthus occidentalis 
Caprifoliaceae 
Viburnum Lentago 
Sambucus canadensis .... 
Sieve Tube 
Type 
2 
3 
2 
2-3 
I 
I 
Wood Paren- 
Vessel Type chyma Distri- 
bution 
the diffuse, or intermediate, position by number 2, and the highest, or 
vasicentric, position by number 3. 
It will be noted in table i that there is considerable discrepancy 
between the classification of material in this study and that given by 
Hemenway. That author, as before stated, places all the woody 
dicotyledons in the two lower types and lists seventy-five genera of 
woody plants, according to sieve-tube type, almost exactly in phylo- 
genetic order. That such an arrangement is not true to fact is shown 
beyond question by the present research, and further, is amply con- 
firmed by an examination of literature. Of the species of woody plants 
placed in types i and 2 by Hemenway, the following species were found 
to have sieve tubes distinctly of type 3, the highest type; Fagus grandi- 
folia, Ulmus americana, Celtis occidentalis, Madura pomifera, Morus 
alba, Sassafras variifolium, Rohinia Pseudo- Acacia, and Ailanthus 
glandulosa. The transverse nature of the sieve plates of Ulmus, 
Madura, Morus, Robinia, and Ailanthus is shown in figs. 16, 18, 19, 
30, and 29 respectively. Further confirmation of the above-cited 
determinations is given in the case of Fagus and Madura by De Bary 
(2), Ulmus, Morus, and Ailanthus by Lecomte (13), and Robinia by 
Strasburger (17). 
An idea of the extent to which the transverse sieve plates are found 
in woody plants is shown in the list given in table 2, compiled from 
Russow (16), Lecomte (13), De Bary (2), Janczewski (10), and Stras- 
burger (17). The names are arranged in phylogenetic order and each 
is followed by the initial of the author referring to it.^ 
4 These same authors also make frequent reference to woody plants having 
sieve tubes with oblique end walls. As this is recognized to be a common type, 
however, a compiled list has been omitted to economize space. 
