LAVENDER. 309 
measure the reduction of temperature, and the plant is matured 
only to the extent sufficient for the purpose for which it is grown. 
Perhaps the suspension of vital action during winter, which must 
be more complete in northern latitudes, as our frosts are more 
severe, tends to preserve certain plants natives of the South, for it 
is observed that all plants are more sensitive to cold when vege- 
tation is active than when it is at rest. The vine is an instance of 
this. On the other hand, when the plant is cultivated further 
south than its natural boundary, the same causes seem to exert 
their influence. Lavender is cultivated on the mountains of Yémen 
in Arabia; the humidity, increasing inversely to the latitude, com- 
pensates the exhaling force of the sun’s rays, and the elevation of 
the locality the effects of the heat. Thus is confirmed, both in 
North and South, the law of vegetable physiology observed by De 
Candolle in the temperate climates of France and published in his 
‘ Essai de Géographie Botanique,’ that “ plants can best resist the 
effects of cold in a dry atmosphere, and the effects of heat ina humid 
atmosphere.’ A mild, damp winter, like the one of 1889-90, does 
more harm than a seasonable frost, as the plants are apt to make 
green shoots prematurely, and the late frosts nip off these tender 
portions, each of which would otherwise have produced a flower- 
spike ; but the frosts of 1890-91 and of 1891-92 were so excep- 
tionally severe that English growers lost many plants. 
The stems and branches of lavender being ligneous and strong, 
are able to resist the force of the wind, and the plant thrives 
best in a perfectly open locality, where the air circulates freely ; 
the oil and resin which it contains enables it to resist the parching 
action of the wind and sun; thus on the most arid and sterile 
ground on the mountain-sides in the South, especially in Spain, 
plants of this genus flourish with more vigour in the season when 
most other vegetation is scorched up by the ardent rays of the sun. 
The L. vera seems to have a predilection for such spots. Certainly 
the plants then assume a more stunted appearance than in richer 
soil, but at the same time the perfume is stronger and sweeter ; 
the calyces become charged with oil-glands aud yield a greater 
abundance of volatile oil. Ina very moist soil the water penetrates 
too much into the tissues, detaches the bark, the plant blackens 
at the root, and a white fungus attaches to the main stem and 
lower branches ; it becomes feeble, diseased, aud dies. A rich soil 
furnishes too much nutriment, the plant grows very straggling and 
