Of course it will be necessary to adjust the Horologium Florae (or Flower clock) to the nature of the climate.  Flowers expand at a later hour in a cold climate than in a warm one.  “A flower,” says Loudon, “that opens at six o’clock in the morning at Senegal, will not open in France or England till eight or nine, nor in Sweden till ten.  A flower that opens at ten o’clock at Senegal will not open in France or England till noon or later, and in Sweden it will not open at all.  And a flower that does not open till noon or later at Senegal will not open at all in France or England.  This seems as if heat or its absence were also (as well as light) an agent in the opening and shutting of flowers; though the opening of such as blow only in the night cannot be attributed to either light or heat.”

The seasons may be marked in a similar manner by their floral representatives.  Mary Howitt quotes as a motto to her poem on Holy Flowers the following example of religious devotion timed by flowers:—­

“Mindful of the pious festivals which our church prescribes,” (says a Franciscan Friar) “I have sought to make these charming objects of floral nature, the time-pieces of my religious calendar, and the mementos of the hastening period of my mortality.  Thus I can light the taper to our Virgin Mother on the blowing of the white snow-drop which opens its floweret at the time of Candlemas; the lady’s smock and the daffodil, remind me of the Annunciation; the blue harebell, of the Festival of St George; the ranunculus, of the Invention of the Cross; the scarlet lychnis, of St. John the Baptist’s day; the white lily, of the Visitation of our Lady, and the Virgin’s bower, of her Assumption; and Michaelmas, Martinmas, Holyrood, and Christmas, have all their appropriate monitors.  I learn the time of day from the shutting of the blossoms of the Star of Jerusalem and the Dandelion, and the hour of the night by the stars.”

Some flowers afford a certain means of determining the state of the atmosphere.  If I understand Mr. Tyas rightly he attributes the following remarks to Hartley Coleridge.—­

“Many species of flowers are admirable barometers.  Most of the bulbous-rooted flowers contract, or close their petals entirely on the approach of rain.  The African marigold indicates rain, if the corolla is closed after seven or eight in the morning.  The common bind-weed closes its flowers on the approach of rain; but the anagallis arvensis, or scarlet pimpernel, is the most sure in its indications as the petals constantly close on the least humidity of the atmosphere.  Barley is also singularly affected by the moisture or dryness of the air.  The awns are furnished with stiff points, all turning towards one end, which extend when moist, and shorten when dry.  The points, too, prevent their receding, so that they are drawn up or forward; as moisture is returned, they advance and so on; indeed they may be actually seen to travel forwards.  The capsules of the geranium furnish admirable barometers.  Fasten the beard, when fully ripe, upon a stand, and it will twist itself, or untwist, according as the air is moist or dry.  The flowers of the chick-weed, convolvulus, and oxalis, or wood sorrel, close their petals on the approach of rain.”