igH James Small. 
by Faivre (1) in the composition, origin, and behaviour under varied 
external conditions. 1 
Transitions from secretory sacs to laticiferous vessels are 
known in the Compositae and the development of this problem may 
assist, as certain other physiological phenomena do, in the elucidation 
of the relationships within the order itself and also of those of the 
order with the Campanulaceae (9, b and f). Considerable progress 
has been made with this phylogenetic problem (9 and unpublished 
work exhibited at the British Association at Newcastle, 1916), 2 
and the results seem to show that there has been an evolution in 
physiology, more or less parallel to that shown by the morphology 
of the groups within the Compositse. As it is obviously necessary 
to know the physiological function of the anatomical structures 
before we can make any deductions of phylogenetic value from 
laticiferous tissue it is intended to extend the present work as much 
as possible within the Campanulaceae and Compositae. 
1 It should be noted that although latex seems to be almost certainly of 
nutritive value in the Compositae it may not have the same function or show 
the same behaviour in other orders. Cf. Parkin (6), on the water-storage 
function of latex in tropical plants. 
2 Some of the preparations discussed above were on exhibition at the 
Newcastle meeting of the British Association, Section K. 
LITERATURE CITED. 
1. Faivre, E. (a) “ Recherches sur la formation du latex et des laticiferes, 
pendant revolution germinative, chez l’embryon du 
Tragopogon porri/oliiis .” Comptes Rendus, Tom. 88, 
1879, p. 269. 
(b) “ Le latex pendant Involution germinative du Tragopogon 
porrifolius, effectuee dans les conditions diverses de 
milieu exterieur.” Comptes Rendus, Tom. 88, 1879, 
p. 369. 
2. Gerber, C. “ Le latex du Figuier, sue pancreatique vegetal & diastase 
proteolytic predominate.” Comptes Rendus, Tom. 
155, 1912, p. 56. 
3. Haberlandt, G. “ Physiological Plant Anatomy.” Eng. Trans., London, 
1914, p. 336, sqq. 
4. Kniep, H. “ Ober die Bedeutung des Milchsafts der Pflanzen.” Flora, 
Bd. 92, 1905, p. 129, sqq. 
5. Mangham, S. “Translocation of Carbohydrates.’’ Science Progress, 
Nos. 18 and 19, 1910-11, pp. 279 and 476. 
6 . Parkin, J. “ Observations on Latex and its Functions.” Annals of 
Botany, Vol. XIV, 1900, p. 193. 
7. Schimper, A. F. W. “ Ueber Biidung und Wanderung der Kohlenhydrate 
in den Laubblattern.” Bot. Zeitung, 1885, Vol. 43 
Col. 739. 
