HEAT OF GROWING PLANTS.

Northland Age, Volume 2, Issue 43, 5 June 1906, Page 2

HEAT OF GROWING PLANTS.

A remarkable instance of the power of growing vegetation is afforded by the Alpine soldanellAS’ tits flowers actually bore, or rather melt, their way through the hard snow. Sometimes, indeed, the flower opens before it reaches the surface, so that it actually blooms in a little hole in the snow. Usually, however, it reaches the surface and hangs out its pretty violet bells above the snow, looking as if it stuck into it. This power of growth through the snow is due to the heat developed by the vegetative process. When the plant begins to send up its flowerstalk in spring the heat of the developing bud melts out a cavity above it. The elongating stem pushes the bud into this cavity, and it goes on melting more snow. This goes on till it reaches the surface. The melted, or partially melted, snow slips down, and freezes again round the stem, which it thus encloses tightly. By careful observation it has been found that the temperature of many flowers is several degrees above that of the surrounding air. This seems to be most marked in the case of an Italian species of arum, in which the temperature may rise over lOOdeg. Far., while outside it is only 60deg. Far. This warmth of the interior of flowers may perhaps explain the mystery of the disappearance and survival of flics, etc., in a spell of cold, wet weather, or on cold nights. Thus when a number of inflated bladderlike calyces of faded flowers of the bladder campion were opened several black flies were found in all but one. They had probably crept in for the sake of the warmth. Other flies habitually resort to flowers as a night shelter. Another curious instance of the penetrating power of growing shoots is often exhibited by snowdrops in a wood. The ground is carpeted with withered leaves from the trees, and in many cases the leaves and flowerstalks of the snowdrops have pierced the leaves, and wear them as collars.—" Globe."