337 
its Applicability to the Ferns , &c. 
Jamaica-Cuba species the next, and the endemics the least. Nearly half the 
endemics are found in one square only. It is of interest to look at the seven 
wides which only occur in one square, and note that as usual one picks out 
the most uncertain species in the flora by this method. Epidendrum ciliare 
is a very conspicuous orchid, but is only recorded on the authority of 
a specimen ‘from Jamaica’ by Shepherd in Kew Herbarium. E. patens is 
assigned by Swartz to Jamaica, but no specimen has been seen. Pelexia 
adnata was found by Masson in 1781, but has never been seen again. 
Pleurothallis Wilsonii is doubtfully identified with the Porto Rico and 
Guadeloupe specimens, and is perhaps more likely an endemic. This leaves 
only three, Vanilla phaeantha , Arpophyllum giganteum , and Epidendj'inn 
Ottonis, all collected by Harris, and therefore reliably recorded. Similarly, 
the one Cuba species that occupied only one square, Pleurothallis foliata , 
was recorded by Wilson (1846-58), and has never been seen again. This 
and others may quite well have been exterminated in the clearances that 
have gone on in the last eighty years. 
Many may express surprise at the small number of squares from which 
even the wides are recorded, when it is realized that there are 3 30 squares 
in the island ; and they may go on to say that further investigation will 
show that my figures are unreliable. But to this, as in the similar cases of 
Ceylon and New Zealand, the reply is simple — is there any reason to 
suppose that collectors deliberately collected wides in preference to Jamaica- 
Cubas, or to endemics ? They are more often recorded simply because 
they occur more often, and there is no shadow of reason to suppose that the 
relative results would be affected by any amount of further investigation. 
And my results depend, not upon absolute figures, but upon comparative. 
There is one endemic genus of Orchids in Jamaica ( Homalopetalum)^ 
and as with other endemic genera in Ceylon and New Zealand, it shows 
less distribution area than the average of the endemics, occupying only two 
squares against an average of three. 
It is thus abundantly clear that my hypothesis of age and area is fully 
borne out by the facts of the orchid flora of Jamaica. 
II. The Flora of the Hawaiian Islands. 
As a further piece of evidence in favour of my hypothesis, and from 
a country which is extraordinarily rich in endemic forms, I have taken the 
Hawaiian islands, employing as a basis the list of plants given in Hille- 
brand’s Flora (5). There are seven chief islands in the group — Niihau, 
Kauai, Oahu (on which is the capital, Honolulu), Molokai, Lanai, Maui, and 
Hawaii. They are separated from each other by stretches of water from 
ten to seventy miles in width, through which pass currents in a north- 
