1866. } Botany and Vegetable Physiology. 397 
plants whose congeners inhabit very distant regions, which have 
recently been discovered in Europe and Asia Minor, and which may 
be truly regarded as disjomted species. The first is the Dzoscorea 
Pyrenaica, Bub., found by M. Bubani, an Italian botanist, on the 
Pyrenees. The genus Dioscorea is very numerous in the tropics, 
only a few species having been found in the temperate zones—for 
example, the Dioscorea villosa, L., in the United States, and the 
Dioscorea Batatas in Japan. No European species was known 
until this one was found in the Pyrenees by M. Bubani. 
Another curious fact is the discovery by M. Kotschy of a 
Pelargonium in the Taurus mountains in Cilicia, the same plant 
having been subsequently found along the whole chain from 
Pamphylia to Armenia. ‘The Pelargoniums, which include the so- 
called Geraniums of our conservatories, were supposed to be exclu- 
sively indigenous to the Southern hemisphere, most of the species 
inhabiting the Cape of Good Hope, and a few Australia. 
The third case mentioned by M. Boissier is that of a Pilostyles, 
a parasitic plant which grows in great abundance upon the branches 
of a leguminous plant, described as an Adesmia, and which Bolero 
collected in Chili. This plant has no root, stem, or leaves, its 
flower is campanulate, about two lines in diameter, and sessile upon 
the bark of the Adesmia, the epidermis of which it tears during its 
development. It belongs to the family Rhizanthee, and is, in fact, 
a miniature representative of the gigantic Raftlesia Arnoldi of 
Sumatra. Another species of the same genus was discovered by the 
naturalist Pohl growing upon the branches of a Bauhinia in the 
forests of Brazil. M. Boissier, in examining a fascicle of dried 
plants brought by M. Haussknecht from the mountains of the east 
of Asia Minor, found the branches of a spiny Astragalus covered 
with a Pilostyles, which on examination he determined to be a new 
species. M. Boissier calls it the Pilostyles Haussknechtii, and it 
completes a genus hitherto known only from South America, and of 
which, singularly enough, all the species are parasitic on leguminous 
shrubs. The Pilostyles is a dicecious plant, and so far only the 
male plant has been found, the female flower remaining still to be 
discovered. 
It would be easy to enlarge this list of disjointed species—that 
is, of species growing isolated in botanical regions far distant from 
the rest of their family or genus. Take, for instance, the well- 
known fact that there is in the floras of Southern Europe only 
a single myrtle and a single laurel, whilst numerous genera and 
species of these shrubs inhabit the tropical and sub-tropical 
countries of both continents. “If, however,” as M. Boissier 
suggests, “ we consider that, in the Tertiary period, the myrtles and 
laurels were diffused in Central Europe, we get a glimpse of an 
explanation, being led to assume—as has been so well shown by 
