THE ORIGIN OF THE FLORA OF ATLANTIC NORTH AMERICA. 309 
deserving of careful examination. A common plant of England is, as 
is well known Bab. Man. ed 6, p. 292 ; Syme. Eng. Bot. vol. viii. p. 46), 
the R. divaricatus of Fries, (R des, Gren. and Godr. ), and R. E Eua. 
as never been recorded for this count I have this autumn had an 
the en rhood of Copenhagen, where it was pointed out to me by 
Professor e, and also near Lund, where I had the great advantage of 
Professor free hous s guidance. I have no hesitation in referring to 
sylvestris a dock collected by Mr. vere near the river Thames between 
Putney and Hammersmith Bridges, Surrey. This presents the characters in 
amarked degree, and fits well with the Danish plant, with an authentic speci- 
men from Wallroth himself in the British Museum, and with plants from 
Dorpat, collected by Gruner, in the same herbarium. In the neighbour- 
Upsala. As Koch states, there are jd ably nu umerous forms with i nte er- 
mediate characters, but the extremes are well-marked and dead distinc- 
tion by British botaniats. —Henry TRIMEN 
MENTHA ALOPECUROIDbEs, Hull. The accompanying specimen of 
Foy was collected by Dr. Dowson and myself near Shalford Common, 
Surrey, during an excursion from Shalford to b oun afew days ago.— 
W. W. Reeves. [New to the flora of Surrey. A well-defined cmm which 
seems to be rare; it has occurred in Kent and Essex. —Ep. Journ. Bor.] 
Extracts and Abstracts. 
THE ORIGIN OF THE FLORA OF ATLANTIC NORTH 
AMERICA. 
The following extract is taken from Professor Asa Gray’s address to 
the American Association for the Advancement of Science, held at Du- 
ood (S. sem, 
of the United Slates, and 
me he remark- 
My speculation 
te Zo 
mp and 
and d perhaps following). I 
ate ancestry, 
liocene times, 
ad that it had ‘beck eal pushed guiar as the temperature 
