PERIODIC PHENOMENA OF VEGETABLE LIFE. 68 



extraordinary circuitistauces, although not so much in the Alps as in 

 large plains. The cultivation of Cereals is restricted within narrow 

 limits by the fall of snow in the spring and autumn. The fear of 

 seeing their corn prevented from ripening by the commencement 

 of a premature winter obliges the inhabitants of the Alps to crop 

 their fields as early and as rapidly as possible. 



The period of spring sowing depending therefore so much 

 upon that of the melting of the snows, which is, in general, very 

 characteristic of the re-appearance of vegetation in the Alps, we 

 have taken it into account in the following tables. 



In investigating the periods of vegetation in different plants, 

 it is necessary to observe in all cases the same moment of do 

 velopment. Many phenomena, the flowering for instance, often 

 last a long while, and in these cases it is always preferable to 

 choose for comparison the commencement of each phenomenon. 

 Take the flowering of the Cherry for instance ; we would not 

 wait till all the branches are quite covered with flowers, but 

 consider the flowering as commenced as soon as it is observed that 

 a considerable number of flowei's are open on each of several trees. 



The data I make use of are all mean results of phenomena 

 observed during several years.* Annual observations give but 

 very uncertain results, as may be seen by the longer series 

 published by Dove and Quetelet. 



Among the earlier observations of the commencement of periods 

 of vegetation in a large number of plants, and their relation 

 to changes in climate, may be mentioned those of Linnaeus, 

 Cotta,f Sennebier,* Schuebler,§ dllombres Firmos.1 Berghaus.l 

 L. Schmoeger, ** V. Gasparin, ff Boussingault. { J and, more 



* All observations made only during short periods arc always noted as 

 such. 



+ Traitv de Mftr'orologie, Paris, 1774, p. 238. 



j Meteorologic Pratique, fourth edition, Paris, 1810, p. 17'2, kc. 



§ Researches on the period of Flowering of several Plants of the Flora of 

 Germany and the adjoining countries. Ratisbon Journal of Botany, 1830, p. 

 351. Several series of observations, more or less detailed, made on the 

 occasion of these researches, by Schuebler, have been published in later 

 volumes of the same Journal. Already iu 1822, in the fifth volume of that 

 periodical, Wenderoth, by his remarks on the Spring Flora of the neigh- 

 bourhood of Marburg, had induced the establishment of a regular course 

 of observation in the gardens of Berlin, Salzburg, Dresden, Ratisbon, Sec. 



|| Reciuil </' Mi moires et Observations Mctr'orologiques, 1838, p. 92. 



«! Almanack for 1840. 



** Meteorological observations made at Ratisbon, from 1774 to 1834, 8vo. 

 1835, table xiv. — Meteorological relations of the Vegetable and Animal 

 Kingdoms, pp. 78 — 82. 



ft Coura d? Agriculture. $ J Economic runde, 2 vols. 1844. 



