OBSERVED m HERTFORDSHIRE IH 1883 . 
195 
obtain reliable comparative results, means should be deduced from 
observations of equal numbers of species. In the following remarks 
on the progress of vegetation during the year, in which the notes 
of our observers will be incorporated, a still further division will 
be made, and I think it will be seen that the periods are sufficiently 
coincident with the months to be acceptable evidence of the 
divergence from the mean dates of the flowering of plants through¬ 
out the period of observation. 
The mean date of flowering of two of the species representing 
February is within the last ten days of January, and their average 
is 15 days early; there are 5 which flower in February, averaging 
18 days early; and 3 the first week in March, averaging 8 days 
early. The great acceleration thus shown so early in the year is 
evidently due to the very mild, though damp and cloudy weather 
which prevailed during the winter months. The snowdrop (78) 
was “ generally in flower in gardens’’ at Odsey on the 28th of 
January, and the dates given in the table for both Odsey and 
Royston are from garden specimens. The flowering of the wych 
elm (71) was “not general” at Hertford, “but there was only 
a tree in flower here and there ” at the date given. 
For March we have 6 species flowering in that month and 4 in 
April, the average of each group being 2 days late. The weather 
in March was much colder, though drier and brighter, than in 
either of the three previous months. Many spring flowers suffered 
from the frost, and to this appears to be due the widely-different 
dates given for some plants, such as the wood-anemone (1), which 
appeared here and there only to be quickly cut off and to have its 
further flowering much retarded. At Royston the sweet violet 
(10) “which had appeared here and there in sheltered spots in 
January, was cut off just as it was coming generally into flower at 
the end of February by the severe frost the first week in March,” 
and “those species, such as the pile wort, which commenced 
flowering at the end of February, were kept at a standstill for a 
month, while many species, which usually commence flowering 
before March is out, waited for, and suddenly burst forth in, the 
warm sunshine of April.” At Harpenden “ the foliage of the dog’s 
mercury and nettle especially suffered, the foliage of many ever¬ 
greens was destroyed, and on the stiffer soils much wheat died 
off; ” but at Hertford “ winter-sown wheat was looking well.” 
To represent April we have only 4 species whose mean date of 
flowering is actually within this month, and their average is 2 days 
late, while the other 6, flowering in May, average 6 days late. 
The effect of the cold weather of March appears therefore to have 
lasted for a considerable period, being most evident at the end of 
April and in the first week of May. The temperature of April 
was about the mean, and it was a very dry month, but not so 
bright as March. At Hertford “ the ash trees generally were fully 
in flower and long before many of the oaks had even burst their 
buds,” but this was not generally the case elsewhere. At Odsey 
the blackthorn (27) on the date given was only “ coming into full 
