Picea 



x 345 



foliage, and numerous leaders occur in alpine regions, and are due either to the 

 severe climate or to constant cropping by goats and sheep. 



3. Witches' brooms on the spruce have hitherto been supposed to be due to the 

 irritation of fungi, bacteria, or mites. Tubeuf, 1 in January 1907, sowed seed which 

 he obtained from a witches' broom that had borne cones. The greater part of the 

 seedlings are normal, but a certain number are dwarf and bushy. Tubeuf supposes 

 that some of the former will in time develop witches' brooms on some of their branches, 

 and that the latter will probably remain dwarf, resembling the varieties 2 Clanbras- 

 siliana, puniila, etc., already referred to as of unknown origin. 



4. Masters 3 gives a figure of a remarkable branch of a spruce, in which the 

 leading shoot had split into two portions for some distance, re-uniting above to form 

 again one stem. 



Distribution 



P. excelsa is a native of Europe, extending from the Pyrenees, Alps, and 

 Balkans northward through south Germany and east Prussia to Scandinavia, and 

 eastward through the Carpathians and Poland to western Russia. 



In France, the spruce occurs in the mountains, mixed with the silver fir, and in 

 the zone above it, the lower limit in the Vosges and Jura being about 2000 ft. It is 

 not at all abundant in the Vosges, where it ascends to 4300 ft. ; but in the Jura 

 covers large areas, and reaches 5000 ft. altitude. It attains its greatest importance 

 in Savoy, which is the only region in France where the spruce is the dominant tree, 

 forming one half of the whole area occupied by forests. The forest of Thones, 4 near 

 Annecy, which I visited in 1904, is one of the best examples of a spruce forest in 

 France; and is treated on the selection system. It contains about 320 acres, lying 

 between 2500 and 4300 ft. elevation on a steep slope, and is a mixture of two-thirds 

 spruce and one-third silver fir. The standing timber is estimated at 7000 cubic ft. 

 per acre, the annual felling averaging 53 cubic ft., with a revolution fixed at 144 

 years. 



The spruce is absent in the Cevennes, and is extremely rare on the north side 

 of the Pyrenees, where it is replaced by fine forests of Pinus montana. Willkomm 

 records it for the Pyrenees of Catalonia and Aragon, where it is not at all common. 

 Its most southerly point in western Europe is the forest of La Cinca, south of 

 Mt. Maladetta in lat. 42 30'. 



In Germany, the northern limit of distribution, beginning in the Vosges, passes 

 through the Pfalz, and after crossing the Rhine at lat. 50 , makes a bend to the west- 

 ward through Westphalia, and reaches the Weser Mountains, where, near Minden, 

 the spruce attains its most northerly point as a wild tree in western Germany, 

 lat. 52 20'. From here the limit passes through Hildesheim, Wolfenbuttel, Walbeck 

 near Magdeburg, and Halberstadt to Altenburg ; whence, taking a north-easterly 

 direction, it is continued through Spremburg and Soran to Ostrowo, reaching the 

 Russian frontier at lat. 52. It then passes northward, parallel with the frontier, to 



1 Cf. Prof. Somerville, in Quart. Journ. Forestry, iv. 309 (1910). 2 Cf. var. tafotlaformis, Carriere, ante p. 1343- 



3 In Card. Chron. xxiii. 274, fig. 52 (1885). ' Cf. Bull. Soc. Forest. Franche-ComU, vii. 630 (1904). 



