GEOGRAPHICAL DISTUIBUTION OF PLANTS. 



163 



by the wind. It delights in moisture; and from 

 tlie time when the bla lo rises a few inches above 

 the surface, the fields in wliich it grows are 

 flooded to the depth of several inches by means 

 of artificial water-courses, provided with sluices. 

 TTie water is not drawn off till the gi-aiu is nearly 

 ripe. Three yeai-s in succession does the soil 

 \ ield a crop of rice without manure ; it is then 

 suffered to remain two years uncovered with 

 ivater, during which time it receives one coat of 

 dung, and becomes spontaneously covered with 

 an abundant, though coarse, herbage. Since an 

 acre of rice is worth, on an average, two acres of 

 wheat, it may be supposed how large a profit 

 attends the cultivation of this grain ; but so de- 

 leterious is the employment to the health of the 

 labourers engaged in it, that the government has 

 prohibited its further extension. Rice can evi- 

 dently be raised only in situations where the 

 land may at jileasure be covered with water. 

 This is an advantage enjoyed by the whole plain 

 of Lombardy, naturally of gi-eat fertility, and 

 rendered still more productive by a system of 

 irrigation more complete, we might almost say 

 more magnificent, than is to be found in any other 

 part of the world. Enclosed between two noble 

 chains of mountains, the Alps to the north and 

 west, the Apennines to the south, the deep and 

 rich soil of this plain seems to have been depo- 

 sited by an inundation which brought down a 

 portion of the substance of those mountains; — 

 consisting, near their bases, of large rounded 

 stones, which gradually diminish in magnitude 

 towards the shores of the gulf of Venice, where 

 the soil consists entirely of finely-divided matter. 

 To the east of Milan this plain is covered with 

 pastures of extraordinary richness, from which 

 is brought the celebrated PaT-mesan cheese. 

 Tliese pa.stures are regularly flooded. The grass 

 is cut no less than four times in the year ; part 

 is made into hay, and part earned green to the 

 cows, which are kept in stalls. In about fifteen 

 years, the herbage, in consequence of this con- 

 tinual watering, becomes too coaree for use ; the 

 land is then ploughed up, and during five years 

 cropped with wheat, oats, maize, hemp, and 

 beans, after which it is again laid down to grass. 

 This admirable system of irrigation, which has 

 rendered northern Italy the most ii-uitful coun- 

 try, perhaps, in the world, was established in 

 very early times. It vras during the flourishing 

 period of the Lombard republics, about the era 

 of our Norman and early Plantagcnet kings, 

 while the greater part of Europe remained yet in 

 a state little short of barbarism, that the design 

 was conceived and executed of this great national 

 work. From each of the lakes that occupy the 

 lower declivities of the Alps, and receive the 

 waters of their innumerable springs, issues one 

 principal canal, which, as it descends, is subdi- 

 vided into a multitude of smaller channels, visit- 



ing every district, every farm, and even every 

 individual field, to each of which the water is 

 admitted at pleasure by sluices ; and having per- 

 formed its office, passes off by another cut, to tha 

 lower land, till it ultimately reaches the Po, 

 which can'ies off the whole drainage of central 

 Lombardy into the gulf of Venice. The banks 

 of these canals ore mostly planted with willows 

 and alders, over which are frequently seen rows 

 of tall poplai-s. The principal canals belong to 

 the government ; the smaller ones are generally 

 the property of individuals, who let or sell the 

 use of the water at so much per hour. 



The cultivation of the olive is bounded to the 

 north by a chain of mountains, extending, with 

 few interruptions, from the Atlantic ocean to 

 the Black sea. This tree is found in every pai-t 

 of Spain and Portugal (with the exception of 

 those districts too much elevated above the level 

 of the sea). It extends over that part of France 

 south of the mountiiins of the Cevennes ; over 

 Italy, south of the Apennines; and Turkey, 

 south of the Ha-mus. A traveller from the north, 

 crossing this chain of mountains for the first 

 time, is surprised and delighted at the new as- 

 pect of vegetation. Gigantic plants of the grass 

 tribe are seen rising to the height of twenty feet 

 and upwards ; the air is perfumed with the blos- 

 soms of the orange and lemon tree ; the myrtle 

 and pomegranate grow wild among the rocks, 

 with the various species of cistus, that beautiful 

 tribe of plants, which afford such a wonderful 

 succession of flowers, opening every morning, 

 and falling off before the close of the day. Tha 

 American aloe here blooms in the open air ; the 

 75, chamcerops humilis af- 



fords the first specimen 

 of the magnificent tro- 

 pical family of palms ; 

 and a few plants may 

 be seen of the date 

 palm of Africa, culti- 

 vated only indeed for 

 oniament, since this 

 tree does not produce 

 fruit on the northern 

 Bide of the Mediterra- 

 nean. It may perhaps 

 be asserted, without exaggeration, that the appear- 

 ance of vegetation exhibits a less striking change 

 in travelling northwards from Piedmont to Lap- 

 land, than in crossing the Maritime Alps from 

 Piedmont to the gulf of Genoa. On the south- 

 ern side of those mountains, the vivid green of 

 our meadows and forests is replaced by the dusky 

 tint of the olive and the evergreen oak, which 

 might, perhaps, be termed sombre, if not con- 

 trasted with the intensely dark indigo colour of 

 a deep and tranquil sea, undisturbed by tides, 

 and resting on a rocky bottom ; — on the other 

 side with the snow-crowned summits of tht 



The Dwarf Palm. 



