500 



APPENDIX 



It is to the sea-bird that we are obliged to appeal in the case of 

 Uncinia, the hooked fruits of which, as is observed below, are well 

 fitted for attachment to a bird's plumage. Yet Sir Joseph Hooker 

 in the case of the flora of Kerguelen, whilst admitting that the winds 

 which blow, as he remarks, from Fuegia to Kerguelen almost through- 

 out the year, are the most powerful natural agents for distributing 

 cryptogamic spores, rejects the agency of the bird. He finds it 

 difficult to imagine how seeds could adhere to birds in their flight of 

 4000 miles across a rough ocean, which is the traverse here implied 

 (Phil. Trans. Roy. Soc, Vol. 168, 1879; see also Hemsley in 

 Chall. Bot., I., 51). Yet the later observations of Moseley, Kidder, 

 and others well illustrate how from their nesting habits in the islands 

 of the Southern Ocean, such as Kerguelen, Tristan da Cunha, etc., 

 albatrosses, petrels, and other sea-birds would be very likely to 

 transport seeds in their plumage, a subject discussed in my work on 

 Plant Dispersal (p. 276, etc.). This would certainly apply to the 

 case of Accena, one of the most typical genera of these regions, 

 the fruits of which, as Moseley observes, stick like burrs to 

 feathers. 



Observation has shown that the hooked fruits of Uncinia may be 

 as firmly entangled in a bird's plumage as those of Acoena. Morris, in 

 a paper in Nature (Dec. 16, 1886) on the dispersal of plants by 

 birds, takes the fruits of Uncinia jamaicensis to illustrate dispersal 

 in a bird's feathers. This species, which has a wide distribution in 

 Central America and in tropical and subtropical South America, 

 grows on the highlands of Jamaica at altitudes of 5000 to 6000 feet. 

 Migratory birds, as he states, on their way north and south between 

 North and South America rest on these Jamaican uplands, and so 

 exhausted are they that they have been easily caught with the 

 hands. In two cases he found small migratory birds on these moun- 

 tains, which were so completely entangled in the hooks of Uncinias 

 that they were unable to escape. Large birds, he says, would break 

 away ; but not without carrying off in their plumage a number of 

 the fruits. The exserted hooked " rachilla " of the fruit is, he says, 

 excellently adapted for catching firmly in plumage. 



Assuming that birds have thus distributed Uncinias over the 

 Southern Ocean, there can be no hesitation in considering that their 

 flight must nearly always have been east before the westerly winds. 

 Under these circumstances one could scarcely look for any very 

 definite arrangement of these and other plants concerned, since 

 Fuegia would be ever supplying them to New Zealand and the 

 intervening islands, and New Zealand would be ever returning them 

 to Fuegia. Yet such an arrangement can be to a small extent 

 detected. Hemsley, though he does not accept the implication, 

 writes that " numerically there is a preponderance of Fuegian forms 

 represented in Kerguelen and the other islands under consideration 

 (Marion, Crozets, Heard), as opposed to what may be termed New 

 Zealand forms " (Chall. Bot., III., 253). The endemic species of these 

 islands, he adds, " exhibit, perhaps, a closer affinity with Fuegian 

 than with New Zealand species." Yet, notwithstanding, he con- 

 siders that " with all the facts before us there does not seem to be a 



