THE 
NEW PHYTOliOGIST 
Vol. 2., No. 2. 
February i6th, 1903. 
RECENT DISCOVERIES OF CAOUTCHOUC IN PLANTS, 
By F. E. Fritsch, B.Sc., Ph. D. 
S INCE Radlkofer * 1 showed that the laticiferous elements of 
Parameria vulneraria contain threads of semi-solid caoutchouc— 
readily observed, when any part of the plant is broken into two, and 
the halves are carefully drawn asunder—similar occurrences have 
been recorded in plants belonging to diverse natural orders. Thus 
Eucommia nlmoides was found to possess such threads 2 3 throughout 
all parts of the plant, whilst Radlkofer in a later paper 2 mentions 
their presence in Wimmeria cyclocarpa and in Plagiopteron (a genus 
at that time included in the heteropetalous Tiliaceae); he further 
adds, that similar threads have been observed by Solerederto occur 
in Salacia micrantha Peyr., as well as in three Hippocrateaceous 
stems belonging to Schenck’s collection of tropical lianes. A 
detailed investigation of the Hippocrateaceae, undertaken by the 
writer some little time back, 4 led to the recognition of the fact that 
these threads occur in a considerable number of species. Finally 
Col 5 6 has quite recently shown them to be present in the genus 
Evonymus , although here, as will be more fully explained below, they 
are not evident except in plants of some years’ growth. These 
recent observations tend to show that the elastic threads of 
caoutchouc are of far more frequent occurrence than was at first 
supposed. This interesting subject seems to me to have been little 
noticed in this country and I therefore propose to devote the 
following pages to a brief description of the essential features. 
1 Radlkofer, Ueber eine Dapknoidee, etc. Sitzungsber. d. 
mathein-pkys. Klasse d. k. k. Akad. d. Wisseusck, Munich, 
Vol. XIV., 1884. p. 515. 
2 Cp. Hooker, leones Plantaruw, 3rd series, Vol. XX., 1890; 
and Weiss in Trans. Linn. Soc. Vol. III., 1892. Part 7. p. 243. 
3 Botanical Gazette. Vol. XVIII., 1893, P- 199-200. 
4 Cp. Bot. Centralblatt. 1901. Beikefte Vol. XI. Part 5. Only 
* dried material was available. 
6 Comptes Rendus des Seances de l’Acad. d. Sciences. Paris, 
June 1901. 
