open all night, probably because their delicate organs would be injured by the sun. The Enotheras, the Gauras, and the different species of the Mirabilis, furnish examples of this kind. Thus too the Cactus opuntia opens its magnificent blossoms at night only, and towards morning shuts them up for ever. The flowers of many plants of the nineteenth class are observed to hang their heads during night — the Camellia, for example - by which means the rain, or dew, which might injure the tender organs of fructification, can run off the more easily. In other plants of this class, the flower shuts up against rain, and on the approach of evening, as is the case with the Marigolds.

The periodical change of colour in some flowers is also worthy of remark. Thus the flowers of the speckled French Honeysuckle (Hedysarum maculatum) are purple in the morning and green at noon. The changeable Hibiscus (Hibiscus mutabilis) is white in the morning, flesh-coloured at noon, and rose-red in the evening. Thus, too, the great Corn-flag (Gladiolus grandis) changes its colour several times in the course of the day.

Neither is the scent of flowers equally strong and agreeable at all hours of the day: many, even of our indigenous flowers, have the strongest scent at night. The Ixia cinnamomea gives out its fragrance in the evening only; the highlyscented Lesser Orpine, (Crassula odoratissima), only in the night; the Epidendrum fragrans, morning and evening; another species of Epidendrum, hung up in a room without earth or water, yields an agreeable perfume for years. The flowers of the Hebenstreitia dentata are scentless in the morning, have a disagreeable smell at noon, and give out in the evening a fragrant odour not unlike that of the Hyacinth:

These properties of flowers, and the opening and shutting of many at particular times of the day, led to the idea of planting them in such a manner as to indicate the succession of the hours, and to make them supply the place of a watch or clock. Those who are disposed to try the experiment may easily compose such a dial by consulting the following Table, comprehending the hours between three in the morning and eight in the evening.

1

Yellow Goat's Beard (Tragopogon luteum)
Common Base Hawkweed (Crepis tectorum)
Field Sowthistle (Sonchus agrestis)
Dandelion (Leontodon Taraxacum)
Alpine Base Hawkweed (Crepis alpina)
Naked-stalked Poppy (Papaver nudicaule)
Orange Day-lily (Hemerocallis fulva)
Red Hawkweed (Hieracium rubrum).
Meadow Goshmore (Hypocharis pratensis)
Red Base Hawkweed (Crepis rubra)
White Water Lily (Nymphaea alba)
White Spiderwort (Anthericum album)
Tongue-leafed Mesembryanthemum (M. lin-
guiforme)

Bearded Mesembryanthemum (M. barbatum)
Dandelion (Leontodon Taraxacum)

Yellow Goat's Beard (Tragopogon luteum)
Field Marigold (Calendula arvensis).
Single-flowered Hawkweed (Hieracium Pilo-
sella)

Red Pink (Dianthus prolifer)

Red Sandwort (Arenaria rubra)

Ice Plant (Mesembryanthemum crystallinum)
Common Base Hawkweed (Crepis tectorum)
Alpine Base Hawkweed (Crepis alpina)
Field Sowthistle (Sonchus agrestis)
Red Pink (Dianthus prolifer)

Red Base Hawkweed (Crepis rubra)
Bearded Mesembryanthemum (M.barbatum)
Single-flowered Hawkweed (Hieracium Pilo-
sella)

Red Sandwort (Arenaria rubra)
Field Marigold (Calendula arvensis)

Tongue-leafed Mesembryanthemum (M. lin
guiforme)

Red Hawkweed (Hieracium rubrum)
Ice Plant (Mesembryanthemum crystallinum)
White Spiderwort (Anthericum album).
Meadow Goshmore (Hypocharis pratensis)
White Water Lily (Nymphaea alba)
Naked-stalked Poppy (Papaver nudicaule)
Orange Day-lily (Hemerocallis fulva)

It is, of course, impossible to ensure the accurate going of such a dial, because the temperature, the driness, and the dampness of the air, have a considerable influence on the opening and shutting of flowers.

INDEX.