APPENDIX. No, V. 481 
sion of these, recourse must be had to natural causes, or such as are uncon- 
nected with human agency. But the necessity of calling in the operation of 
these causes implies the adoption of that theory according to which each 
species of plants is originally produced in one spot only, from which it is gra- 
dually propagated. Whether this be the only, or the most probable opinion 
that can be held, it is not my intention to enquire: it may however be stated 
as not unfavourable to it, that, of the Dicotyledonous plants of the lists, a con- 
siderable number have the embryo of the seed highly developed, and at the 
same time well protected by the texture of its integuments. 
This is the case in Malvacese, Conyolvulacex, and particularly in Legumi- 
nosx, which is also the most numerous family in the lists, and im several of 
whose species, as Guilandina Bonduc, and Abrus precatorius, the two conditions 
of developement and protection of the embryo coexist in so remarkable a de- 
gree, that I have no doubt the seeds of these plants would retain their vitality 
for a great length of time, either in the currents of the ocean,* or in the di- 
gestive organs of birds and other animals; the only means apparently by 
which their transportation from one continent to another can be effected : and 
it is deserving of notice that these seem to be the two most general plants 
on the shores of all equinoctial countries. 
The Dicotyledonous plants in the lists which belong to other families have 
the embryo of the seed apparently less advanced, but yet in a state of consider- 
able developement, indicated either by the entire want or scanty remains of 
albumen: the only exception to this being Leea, in which the embryo is 
many times exceeded in size by the albumen. 
In the Monocotyledonous plants, on the other hand, consisting of Graminee, 
Cyperacez, Gloriosa, Flagellaria and Pistia, the embryo bears a very small 
proportion to the mass of the seed, which is formed of albumen, generally 
farinaceous- But it may here be observed that the existence of a copious 
albumen in Monocotyledones does not equally imply an inferior degree of 
* Sir Joseph Banks informs me, that he received some years ago the drawing of a 
plant, which his correspondent assured him was raised from a seed found on the west 
coast of Ireland, and that the plant was indisputably Guilandina Bonduc. Linnzus also 
seems to have been acquainted with other instances of germination having taken place 
in seeds thrown on shore on the coast of Norway. Vide Colonie Plantarum, p. 3, in 
Aman. Acad, vol. 8. . 
3Q 
