GEOGRAPHY OF PLANTS. 491 



The only anomaly apparent in the table respects the date of blooming and 

 ripeuino- of the Isabella. The first by comparison with several warmer locali- 

 ties is antedated, perhaps, one week, and the date of maturity may safely be 

 assumed as quite two weeks too early. Dr. Underbill, of Croton Point vine- 

 yards, on the Hudson, informs us that the Isabella blooms from the 14th to the 

 25th of June, and though the fruit is gathered for market from the 14th to the 

 25th of September, it continues to ripen for five or six weeks. At Kelley's 

 island. Lake Erie, another celebrated locality where the Isabella is successfully 

 cultivated and ripened, as we are informed by George C. Huntington, the 

 Isabella and Catawba almost uniformly bloom ©n the 20th of June, and that 

 the first does not mature even under a higher heat than that known at Water- 

 loo, New York, until the 15th of October, and that they improve even until 

 the 15th of November.* Both Croton Point and Kelley's island are more 

 favorably situated for early blooming and ripening than is Waterloo, and yet 

 at the former the Isabella blooms and ripens later. The observed temperature 

 is not, therefore, in this instance, a correct index to the wants of the Isabella, 

 because the vine observed was exposed to reflected heat, which raised its tem- 

 perature 10°, and assimilated its surroundings to those of more southern locali- 

 ties. As an evidence of the value of shelter, this illustration is worthy of 

 remark. The fruit is reported perfectly ripe under the observed temperature, 

 which coidd not have matured it without the increment derived from shelter. 



Observations made on the vine at Brussels show that it pushed its first 

 leaves at a mean date of April 25 for a series of years from 1841 to 1850, 

 and that during this term the heat of the atmosphere in the shade was a mean 

 of 10.25° centigrade, or 50.45° Fahrenheit. This mean was preceded by a 

 sum of temperature which may be esteemed uninfluential, that for March 

 having been almost as low as 6° centigrade, or 42.80° Fahrenheit. 



The minimum temperature at which the vine commences foliation, according 

 to Count de Gaspariu, is 9.5° centigrade, or 49.10° Fahrenheit. Boussingault 

 admits that the 1st of April may be considered the point of departure for the com- 

 mencement of the growth of the vine in the department of the Lower Rhine, where 

 his experiments Avere made, and that in order to favor its growth this period 

 should have a mean temperature of 7.5° centigrade, or 45.50° Fahrenheit, ac- 

 cording to observations made at Strasburg. De Candolle believes that the 

 minimum temperature at the time of commencing vegetation in the spring may 

 be that of 8° centigrade, or 4G.40° Fahrenheit. He, however, inclines to the 

 belief that 10° centigrade, or 50® Fahrenheit may be considered the tem- 

 perature at which the vegetation of the vine properly commences, and such we 

 liud to be the case in our own experience with our native varieties. At this 

 date (April 24, 1864) the buds of the Concord vines are much swollen ; some 

 of them have opened, and several other varieties are in various stages of en- 

 lai-gement, but without showing the leaf. The daily mean temperature for the 

 past seven days has been 11.5° centigrade, or 53.76'' Fahrenheit, and for the 

 past tw9 weeks 10.25° centigrade, or 50.42° Fahrenheit, and yesterday the 

 peach blossoms expanded, and to-day the first bloom of the pear appeared 



* At Kelley's islaud Isabella and Catawba leaf May 5 and 6, respactively, bloom June 20, 

 ripen October 15 and November 1, respectively. By known mean temperatures and aggre- 

 gates of heat calculated therefrom we learn that the Isabella requires 10,639 degrees, and the 

 Catawba 11,307 degrees, Fahrenheit, from leafing to ripening. These are evidently the sums 

 of heat required in the open vineyard, and are proved to be perfectly in accordance with the 

 results of observation made at Croton Point and Poughkeepsie, New York, and at Haddon- 

 iield, New Jersey. 



Since the above was written, F. C. Brehm, of Waterloo, informs that he has destroyed 

 nearly every Isabella in his vineyard, as they do not succeed on his rich soil. He also informs 

 that the Diana ripens two weeks earlier than the generality of Isabellas, by which we may 

 fix the date of ripening of the Isabella in the open vineyard at Waterloo at October 4 and 

 thereafter, which is more in accordance with experiments elsewhere. 



