1886.] BOTANICAL GAZETTE, 201 
greater proximity and readier accessibility to the mainland, as 
might be expected, it shows a larger preponderance of conti- 
he outward channel to Clemente is often boisterous in the 
extreme ; and the long, unbroken surges of the Pacific give the 
squeamish traveler in a small boat the full flavor of a protracted 
sea voyage. 
_ Nearly identical climatic conditions prevail on all three; 
cooler in winter than the mainland, hotter and drier in summer 
on the south sides, owing to the deflection of the cooling fogs by 
the mountain tops. 
revailing winds and ocean currents are similar to those 
affecting Guadalupe, and whose nature and influence has been so 
clearly and ably set forth by Mr. Watson, that I can not do other- 
wise than refer for the details to his admirable paper.’ Therein 
he shows the nature of our prevailing winds are in every way 
antagonistic to the introduction of continental species to Guada- 
upe; curiously he seems to have overlooked the converse of this 
proposition, which would be that this agency would actively favor 
the distribution of insular species to the mainland. 
hilst recognizing as a factor, I am of opinion that the value 
attached by authors to the common media of seed transmission, 
i. @, agency of man, beasts, birds, watery currents and winds, is 
somewhat over-estimated; the history of our island plants tends 
to confirm and strengthen this belief. 
wir kL. e case of Malacothrizx insularis Greene, and Lavatera in- 
sularis Wats. confined to the Coronados Isles, though only dis- 
fant seven miles from the mainland. 
. The limitation of at least three well-defined species to 
Cedros,’ which with the island of Natiridad forms the western 
barrier of San Sebastian bay, Lower. California, and whose to- 
pography would seem to indicate that at no distant epoch they 
formed a continuous part of the mainland. ; 
. A new species of Pentacheta, found originally near San 
Pedro in the spring of 1884 and confined to the area of a few 
square yards, was the following year traced to its original habitat 
on Catalina Island. The spot where found on the mainland has 
been for twenty-five years past constantly used for pasturing 
* Proc. Am. Acad. 1. ¢., p. 107. 
* Veatehia Cedrosensis, Enott Ced 
No account is taken of Krynitzkia Cedrosensis Greene, 1 
mainland neg ee sere! poet aenh en our consideration ; 
inland ; s is regretiully exciude yur consideration ; 
iS cher ul the rait taken’ peculiar ; available for artificial distribution re 
a establishment of a well-defined species so near the mainland, yet limited to the 
nd, would bea potent argument in behalf of the opinion expressed. ee 
+, Cod cite 
ess on account of its doubtful 
‘orms have been collected 
26 
