202 BOTANICAL GAZETTE. [ August, 
sheep just disembarked from that island, and the case cited is 
probably as direct evidence of the agency of animals in seed dis- 
tribution as any that could be quoted; nevertheless, with every 
circumstance conspiring during very many years to favor its 
introduction in manifold, the total “ crop” of 1884 might readily 
have been the product of one fertile akene growing and maturing 
the previous year! 
4, Prunus occidentalis is a species which, from its abundance, 
gives character to the vegetation in parts of Catalina. Its great 
size (25 feet) and conspicuous beauty seem to preclude the possi- 
bility of its having escaped the notice of the most unobservant 
explorers of islands to the north or south, and it is probably safe 
to assume its confinement to this island alone of all on our west- 
ern coast, yet it is reported to me as native of the West Indies. 
The abundance of young and flourishing seedlings indicate that: 
it germinates readily ; while its large and luscious drupe greedily 
fed upon by squirrels, sheep, goats, birds and man would seem to 
provoke its widespread and rapid distribution. It grows far up 
on the roughest interior mountain ridges at an elevation of 3,000 
feet, and down the fertile valleys and cafions to the very water’s 
edge; at all altitudes and all exposures it flourishes with un- 
equaled vigor, yet no trace of it exists on Bird Island, barely 
two miles distant.* 
5. A somewhat analagous case is that of the Lavateras. This 
genus is largely represented on most of our western islands, from 
nacapa on the north to San Benito, Lower California, on the 
south, with probably no congener on the mainland other thap 
escapes from gardens where it has been largely planted. Yet the 
us is indigenous to the south of Europe and adjacent islands: 
that it should owe its presence in the occident to the common 
methods of seed dispersion and leave no trace upon intervening 
continents is somewhat improbable: that it is due to systematic 
transplantation upon uninhabited islands is more than improbable 
—it is an unreasonable supposition. 
_ That a great ocean is not an insurmountable barrier to the 
migration of species is a fact commonly known. A single Asiatic 
ee of Castilleia illustrates it; yet that genus sweeps along 
e whole western coast of North and South America, from Arctic 
to Antarctic zones, and the chances have weighed heavily in its 
favor of finding an outlet from ‘some of its myriad sources: 00 
such conditions, however, obtain in the case of the Lavatera or 
__ 8 For the benefit of botanists who have not seen it I wish to that P. occidentalis is & 
hy Mya edseap ly degeneracies ey cathabeons Weaves and white noes 
‘ oran . an 
pe aap way comparable to an o: nie. n Some valleys it forms unique Pp 
