CELLS OF EUCOMMIA ULMOIDES, OLIVER. 253 
latex cells have been derived from such cells as have been described, it would seem that 
their primary function was to store up the waste products, or, at all events, to secrete 
some substance which would render the leaves distasteful, and, therefore, more or less 
immune. When the laticiferous system, however, was elaborated to form a continuous 
system throughout the plant, whether as articulated vessels or non-»rticulated cells, the 
secondary function of food conduction may have been added to their first and primary 
function of protection. 
How do the foregoing observations affect the systematic position of Eucommia ? 
Professor Oliver, from the scanty material with which he had to deal, especially owing 
to the absence of flowers, did not definitely assign Eucommia to any natural order, 
but suggested that it might have affinities with the Euphorbiacez, and perhaps more 
especially with the Phyllanthoidez. If the cells described have any morphological 
affinity with the latex cells of Euphorbiaces, they would tend to support Professor 
Oliver's suggestion that this plant might be associated with the Euphorbiacere. 
The Phyllanthoidez, however, according to Pax * are devoid of laticiferous tissues ; 
we should therefore have to include Еисоттіа among the Crotonoidez, which have 
some laticiferous tissue, however elementary, and if we were to lay as much stress on 
the anatomical character of the laticiferous tissue as Pax does in his paper in Engler's 
* Jahrbuch’ we might place it either in a group at the side of the Johannesiez, or between 
the Johannesieze and the Hippomane:e. 
As, however, no flowers are to hand, these suggestions are merely speculative, and at 
present practically valueless ; for, if we adopt Chauveaud's classification of the laticiferous 
tissues, we might associate Еисоттиа, as possessing “tubes continus ultérieurs," with 
either Cannabis, Urtica, or Vinca. Тһе value of these anatomical characters in 
classification сап only be secondary. Still, as they have their function as secondary 
characters, it may be as well to mention that in Eucommia we find no medullary phloem 
groups, and that the secondary phloem presents distinct masses, hard bast elements 
alternating with the soft bast. 
In conclusion, I take this opportunity of thanking the Director of the Royal Gardens 
of Kew for putting this interesting material at my disposal, and I wish also to acknow- 
ledge the help and suggestions I received during my investigations from Professor F. W. 
Oliver. 
* Е. Pax in Engler’s Bot. Jahrb. (1884) p. 404, and in * Engler's Natürliche Pflanzenfamilien,’ vol. iii. p. 5. 
