enomena generally follow one another in the same order. And it follows
that those which occur together any one year, will occur at or nearly
[at] the same time every other." This indeed is what we might expect,
from the circumstances of any interruption in the time of their
occurrence, due to seasonal influence, necessarily affecting them all
equally. One of the examples by which he supports his view is the
parallel behaviour of the ground-ivy (_Nepeta Glechoma_) and the
box-tree, whose flowers appear simultaneously on 3rd April, as an average
date; while in a certain backward year they flowered later, but still
close together--namely, 20th April and 19th April. There is to me an
especial charm in these duets. Thus I like to imagine that the larch is
waiting to put on its new green clothes till it hears the black-cap. Or
is it that the larch rules the orchestra, and with his green baton
signals to the songster to strike into the symphony? {11}

Shakespeare is right to make the daffodil come before the swallow dares,
since according to Blomefield the average of seventeen annual
observations gives 12th March for the daffodil's flowering-day, and the
swallow does not appear till 9th April at the earliest. Browning, too,
is scientifically safe in letting his chaffinch sing now "that the lowest
boughs and the brushwood sheaf round the elm-tree bole are in tiny leaf."
Indeed, the most dilatory chaffinch must have been singing since 19th
February, and in fortunate seasons might have been heard on 7th January.
A floral calendar may be useful as an interpreter in antiquarian
problems. Thus Blomefield {12a} says that "the _flos-cuculi_, or
cuckoo-flower of the older botanists, was so called from its opening its
flowers about the time of the cuckoo's commencing his call." The
botanist referred to may have been Gerarde, and the flower seems to be
_Cardamine pratensis_, known as lady's smock, also as the cuckoo-flower.
Now the cuckoo begins his song (as the average of Blomefield's seventeen
years' observation near Cambridge) on 29th April, {12b} and lady's smock
blossoms 19th April. {12c} The coincidence is but moderate, but it is
cheering to find in Gilbert White's _Calendar_, with its earlier South
Country dates, that the events occur together: lady's smock, 6th to 20th
April; cuckoo, 7th to 26th April.

Wood-sorrel (_Oxalis acetosella_) was known as cuckoo-sorrel by the
Saxons. In Stillingfleet's _Calendar of Flora_ (1