209 
The plant cultivated here is easy of cultivation from cuttings or 
seed, but it has never established itself, though cultivated commonly 
for upwards of 30 years or probably more, and it has by no means 
the rapid growth attributed to it in Mexico. 
It is a shrubby climber readily forming a thick bush, and appar 
ently requires to be treated by a special process something like that 
employed for Guayule. The plant is too small to tap. but the Pro- 
posal is to crush out the latex. In crushing, however, the gLeen juice 
of the plant combines with the latex and the rubber fails to coagulate. 
However, this difficulty has apparently been overcome, as good rubber 
has been obtained from it. There seems to be little doubt that the 
plant was originally a native of Madagascar but perhaps of India 
also. Mr. Dolley, however, is in error in stating that “ In India it is 
called Palay, a Malayan word and I believe written incorrectly Pulay 
or Palai.” Palay is not a Malay word, and there is no name for 
the plant in Malay as it is only known of recent years in the Malay 
region. 
It is hardly likely that the plant would ever come into cultiva- 
tion as a source of rubber in this part of the world, but if it has run 
wild to the extent described by Mr. Dolley, in Mexico, it might cer- 
tainly be worth while working up there. - Ed. 
LONGEVITY OF SEEDS. 
An important contribution jo our knowledge of the longevity of 
seeds and the structure of the seed-coat is published by Miss Bertha 
Rees in the proceedings of the Royal Society of Victoria 23, II, p. 393- 
In an earlier paper Professor Ewart divided seeds into three classes. 
Microbiotic seeds which do not live for more than 3 years. 
Mesobiotic seeds which last from 3 to 15 years. 
Macrobiotic seeds which may be able to germinate from 15 to 100 
years. 
All the hard seeds are included in the last class. These seeds do 
not swell when soaked in water. They are more abundant in a dry 
climate than a wet one and seeds of the same species may vary in 
hardness according to the climate in which they are grown. Plants 
with hard seeds are most abundant among the Legumitiosae, but occur 
in other orders. The hardness of the seed is due in most cases to the 
presence of an outer membrane or cuticle, but in Canna seed the ends 
of the outer layer of long cells (palisade cells) are hardened and 
there is no true cuticle. This cuticle is believed to be formed bv the 
deposition of particles of wax or fat in the cell walls. This prevents 
the introduction of water. 
In order to let the water into the seed and so start the germina- 
tion, several methods can be used. The most practical way is to 
