1909. Adams. — Distinguishiyig Plants in Ireland. 131 



that the Flora of Krakatau and neighbouring islands, in 1906, 

 consisted of 137 species, of which 39 per cent, were brought 

 by oceanic currents, 30 per cent, by wind, and 19 per cent by 

 birds. The vegetation of these islands was entirely destroyed 

 by volcanic eruptions in the 5^ear 1883. 



{d) Hooked fruits are carried on the fur or feathers of 

 animals. Fleshy fruits are eaten by birds, and the seeds ger- 

 minate after passing through their bodies. This occurs in the 

 case of Ivy and Hawthorn. But the subject of the feeding 

 habits of our native birds is still in its infanc}', and we have 

 much to learn of the part they play in seed dispersal. It seems 

 possible that the migratory birds may occasionally introduce 

 seeds into Ireland in this way, and some of these may possibly 

 be killed by hawks before the seeds are digested. 



Darwin, in his Origm of Species, states that fresh-water fish 

 eat the seeds of yellow Water-Lily and Potamogeton. He 

 does not state what species of fish, or whether the seeds will 

 germinate after passing through their bodies. 



It will be evident that many further observations must be 

 made before we can answer the eleven questions outlined 

 above. When we can answer these questions satisfactorily it 

 will then be possible to say from the evidence, with a reason- 

 able amount of certainty, whether such and such a species is 

 a Native or an Alien. 



BlBI^lOGRAPHY, 



Anonymous. — Remarks on the Nationality or Nativity, Denizensbip or 



Citizenship of Plants. — Phytologist, N.S , vol. i., 1855-6. 

 Carpenter, G. H. — The Mingling of the North and the South. — /r, AW., 



voL v., 1896. 

 De CandoIvLE, a.— Geographic Botanique, chap, viii., 1855. 

 Dunn, S. T.— The Alien Flora of Britain.— 1905. 



Ernst, A. — The New Flora of the volcanic island of Krakatau. — 1908. 

 Guppv, H. B. — The River Thames as an Agent in Plant Dispersal. — 



lourtt. Linn. Soc. (BoL), vol. xxix., 1892. 

 Knowles, M. C— a Contribution towards the Alien Flora of Ireland. — 



Ir. Nat., vol. xv., 1906. 

 lyEES, E. — Records of Observations on Plants appearing on uewl} broken 



ground, raised embankments, deposits of soil, &:c. — Phytologist, vol. 



iv., 1 85 1. 

 Moore, D. — Observations on some plants considered by M, De Candolle 



to be alien and introduced into Britain, — Nat. Hist. Review., vol. vi., 



1859- 



