Za 
Thermal constants for the blossoming and ripening of 889 plants, etc.—Continued. 
Flowering. Ripening. 
at : F é = | ee 
Designation of plant: order, genus, and species. A . 
‘ . Con- Con 
Date. Date 
stant. | cola as tert: 
| | = 
<OV ilionacex [G.—; see G. 32]—Cor.tinued. Sey Reve: 
XCVII. Papilionacex [G.—; see G. 32]—Cortinued | °Réaum. | | °Réaum. 
(eee Cercisicamadensishas.<s.28.-5...c0--e---esee eee seeeene- May 8 | 449 | BR se on| aS aae8 se - 
(Soo) Cercisisiliquasirumely)< 2225.2 case ac cilacici- see ce sc ee es May 16 | 5 Oct. 75 2,430 
(887) Gleditschia triacanthos L. inermis ...........-..------- June 5 | 756 | Sept. 20 2, 332 
(888)2. Gymnocladus canadensis: Gam. :..-4.-----------5------ June 4 | OS seas ae |: ere 
CSeo Meacsiann amyl WiGa asc axcnq- 28 c\o2 2 ssacieie asi conc ¢ July — | 1, 631 | Saboooesor||Sascecnrce 
7. The fruit ripens during the following season. 
168 and 175. Did not bloom during the ten years. 
179 and 189. Tree too young to blossom. 
203. The concealed blossoms can not be accurately observed. 
270 and 271. The dates of blossoming are too variable to allow of determining a thermal constant. 
304. These figures obtain for moist years, but for dry years we have September 9 and 2237, respec- 
tively. 
308. Blossomed only once during these ten years. 
518. The blossoming of the tree is not easy to observe. 
577. The tree died in 1855. 
580 and 581. Too young to blossom. 
702 and 775. Did not blossom. 
716. Blossomed only once and died in 1857. 
756. Did not blossom and died in 1856. 
800. Dates are too variable to allow determining a thermal constant. 
834 and 880. The dates when the hull hardens and colors and when it springs open, allowing the 
fruit to fall, are both given. 
54. Very rarely blossoms. 
5 
LINSSER. 
The most elaborate and, I believe, the most important investigation 
into the relation between plant life and climate is that published by 
Karl Linsser in a first memoir (St. Petersburg, 1867) and in a sec- 
ond memoir of 1869. My personal association with him during 1865 
and 1866 greatly stimulated my own early interest in the subject. 
The conclusions arrived at by Linsser are based upon the study of all 
available European observations. His knowledge of physics and 
skill in numerical computations as the chief of the computing divi- 
sion of the Imperial Astronomical Observatory at Poulkova has 
given his results a precision based on the well-established principles 
of probabilities and a clearness of interpretation that specially com- 
mend them to the physiological botanist. Linsser states that the 
principal hypotheses that had up to his time been framed as to the 
form of the connection between the phenomena of temperature and of 
phenology are the following three: 
(1) That for the same plant the same stage of vegetation occurs 
from year to year on the attainment of the same mean daily temper- 
ature. 
