372 JOURNAL OF SCIENCE. 
probably a species descended from some variety of L. scoparitwm— 
a variety in which the hard tip of the leaf, which was of no 
further use to it, has been lost. Along with this variation 
are others in the habit of the plant, in its flowers and its 
fruits ;—for example, its flowers are smaller and less conspi- 
cuous, and I have reason to believe they are not so absolutely 
dependent on insects for their fertilization as the species of wider: 
range. And this, indeed, we might expect, seeing that this country, 
as compared with other lands, is deficient in many groups of flower 
visiting insects. At any rate, here is the phenomenon of two species 
of the same genus growing side by side, the one having a wide range 
outside of these islands, and the other being endemic, and as far 
as I can see, the only explanation of their occurrence lies in this 
evolutionary theory. 
Here we have a plant of what is sometimes called—but very 
erroneously—Chatham Island Lily (Myosotidium nobile). It is, as you 
see, a large handsome Forget-me-Not. One of the characteristic 
features of the order (Boraginez) to which the Forget-me-Not belongs, 
is the presence on nearly all parts of the plants of rough hairs, which 
no doubt serve to protect them against many insect enemies. But 
our Myosotidium has lost its hairs, one result of which is that in our 
gardens it is a most difficult thing to keep the plant alive, because it 
falls such an easy and grateful prey to the mandibles of insccts. 
This plant is only found in the Chatham Islands and on the Snares, 
and the singular thing about it is, that its nearest allies are not the 
Forget-me-Nots of New Zealand, of which there are over a dozen 
species, but the various species of the genus Cynoglossum, or Hound’s 
tongue. Now this genus occurs in Australia and many other parts 
of the Old World (including Britain), but is not found in New 
Zealand, and a marked feature is, that all the species are very hairy. 
The only explanation of such a singular distribution appears to me to 
be something like the following. A species of Cynoglossum had at 
some far remote period—when New Zealand extended to the east of 
the present Chatham Islands—been introduced into the country, and 
had spread over it, probably keeping near the sea, as many of our 
Forget-me-Nots do. Ata later period—probably after the Chathams 
had. been isolated—some species of insects which fed on the plant had 
been introduced, or some other equally potent cause had come into 
operation—by means of which the plant was exterminated from 
New Zealand proper, and only survived in the Chathams and 
similar outlying spots. Like the Moas, Notornis, and other 
interesting forms of life, this species is on its way to extinction, 
unless where protected by the hand of man. Now none of the older 
theories of biology will explain such facts of distribution as the few | 
examples I have adduced, and, therefore, we put this subject of Geo- 
graphical Distribution forward as one of the strong points of the 
Doctrine of Evolution. I have only adduced two or three examples, 
but I think they will serve to show you what interesting questions the 
botanist meets with when he investigates the distribution of plants. 
To trace out the history of any one of our hundreds of species of 
plants requires a knowledge on our part of the structure and distri- 
bution of its allies, and such a knowledge requires us to become 
familiar with the geographical range of the allied species. The 
