340 ILLUSTRATIONS OF THE BOTANY OF [Datiscee. 
the top of the. trunk of a lofty Banyan, out of which it appears to be growing; 
though actually older, and like it, having its roots fixed in the ground. The Lac 
insect delights in several species of Ficus, as F. indica, religiosa, glomerata, &c.; the 
twigs of which it may frequently be seen covering. Broussonetia papyrifera affords 
fibres, which are convertible into ropes; made into a kind of cloth; or manufactured 
into paper. Urticee and Artocarpee are now re-united by M. Gaudichaud and Dr. Lindley. 
155. DATISCEZ. 
This small order was formed by Mr. Brown of the genus from which it is named, 
and Tetrameles, discovered by Dr. Horsfield, in Java. Datisca is found both in the 
Old and New World, existing in the latter in Pennsylvania. D.cannabina, so named 
from its great resemblance to the Hemp-plant, extends from the south of Europe and 
Asia Minor through Iberia to the vallies of the Himalaya. I have obtained it from 
Cashmere and Kunawur, and found it at the foot of the Choor and Kedarkanta moun- 
tains. It spreads also to Nepal ; D. nepalensis, Don, being the same species. 
“él. 
found in their favourite food, the mulberry leaf, ‘even though this is represented as being without n i k: r juice, 
and subsequently requested Mr. Sievier, who was living out of town, to ascertain whether any Caoutchoue did 
exist in the juice of the mulberry: a few days afterwards, he informed me that I was perfectly correct in my 
inference, as the juice of the mulberry not only contained Caoutchouc, but was also milky, as might be seen 
on breaking the petioles of the leaves, especially on dry and bright sunny days. This fact may partly explain 
why mulberry leaves, grown on dry, sandy, or gravelly situations, and even on the higher lands in the south 
of France, are more nourishing to the silk-worm, than those produced in rich or moist lands ; the latter, from 
their quicker growth, being more watery, and therefore not so favourable for the production of the peculiar 
secretions of the mulberry. i 
On reading the above paper, the Rev. F. Hope, late President of the Entomological Society, inquired 
whether the Spindle-tree, Euonymus europea, belonged to any of the above families of plants, as it was 
occasionally employed for feeding the silk-worm. This would at first sight, appear to be an exception ; but it 
may be observed, that Caoutchouc is a substance much more extensively diffused in plants than is generally 
supposed ; also, that the Tusseh silk-worm, Phalena Paphia, described by Dr. Roxburgh (Trans. of the Lin. 
Soc. vol. vii.) feeds on Zizyphus Jujuba; and though the former, Euonymus, is now placed in Celastrince, 
p. 166, and Zizyphus in Rhamnew, p.168, these two families are so closely allied to one another, as to have 
formed the Rhamni of Jussieu ; and both are allied to the J. licinee, a tribe of Celastrinew, according to De Candolle 
(v. p. 167), and which contains the common holly, so well known as employed in making bird-lime. This 
substance (g/« of French chemists) is very analogous to’ Caoutchouc, or only a modification of the latter. The 
Bughy silk-worm of the natives of the Birbhoom Hills, where Tusseh silk is manufactured, however, feeds 
on Pentaptera glabra (Ascen of the natives) of the family of Combretacee ; but we do not know that any of 
these contain Caoutchouc; though I have no doubt that some will be found in these plants. The subject is well 
worthy of investigation, especially as shewing the important inferences we may sometimes draw from the 
natural affinities of plants; and also, in a practical point of view, as assisting us in finding fit food for the 
fastidious silk-worm ; and therefore extending the silk cultivation’ into new situations. The number of plants 
suited to silk-worms may, I think, be increased, by experimenting on those belonging to families which 
yield Caoutchouc. It does not follow that all which yield this substance are fitted for its food; for many 
we have seen are united with an acrid principle : and the surface of the leaves of others may be both too 
rough, as well as the texture too thick and hard for so delicate a tribe of animals, 
156. Utmacrez. 
