16 BRITISH EOCENE FLORA. 



and Araucarias, Podocarps, Dammaras, and Dacryds occupy corresponding tracts in the 

 South, No genus inhabits the plains of the Tropics ; they belong essentially to the 

 Temperate and Subarctic Zones. In northern regions the members of this group out- 

 number the broad-leaved trees by ten to one ; and even on the Pacific slopes of America 

 extensive tracts are densely wooded by them, with scarcely any admixture of deciduous 

 trees. The Pine-barrens of North America and the belt of Conifers in Northern Europe 

 and Asia stretch almost continuously across the two continents, ceasing only with the 

 limits of vegetation. 



Notwithstanding the enormous areas still occupied by Coniferae, instances are 

 abundant of the areas of their growth and number of individuals becoming very sensibly 

 lessened through contact with man or from changes of climate. The. extinction of Abies 

 pedinata and A. excelsa in England was probably due to a failure of heat. The diminu- 

 tion of Taxus baccata (the Yew) in England, and of many once common Pines and Firs 

 in France, Switzerland, and Spain, the Cedars in Lebanon, and of the native Juniper and 

 Yew in Madeira, are due to the agency of man. The limit at which Conifers cease to grow 

 in Alpine forests in Switzerland is everywhere retreating towards the valleys, for Pines are 

 not dwarfed there towards their superior limits, and do not creep as bushes to the verge of 

 the snow-level as on other mountain ranges and towards the poles ; but isolated and 

 grand old Pines and Larches stand out In exceptional vigour beyond the rest. In many 

 of these regions remains of large trees exist far above the limits of present forest vegeta- 

 tion ; and the names of some now bare heights and valleys indicate their former wooded 

 nature. In Siberia, on the other hand, the Larches seem to be creeping still farther 

 north as trailing shrubs, and are now among the hardiest trees in existence. 



Their majesty, symmetry, or fairy grace, their resinous fragrance, and their dry and 

 open character give to Coniferous forests a charm seldom possessed by the often bare or 

 dankly decaying forests of deciduous trees. 



The stupendous size that individual Conifers attain has long excited wonder, though 

 this is actually understated in text-books. Specimens have been seen of Abies Bouglasii 

 309 feet in height, A. Menziesii 318 feet, Picea grandis 321 feet, P. nobilis 

 about the same, Pinus Lambertiana 300 feet, and Thuya gigantea 325 feet ; while the 

 Sequoias are reputed to reach 400 feet, exceeding every forest tree in solid masses of 

 timber. The Himalayan Pine and Deodar reach 200 feet ; and some of the Podocarps 

 of New Zealand also attain that height ; while the Chilian Araucaria is said to exceed 

 260 feet. In Europe the extreme height recorded for any Conifer is 180 feet, the 

 common Spruce and the Silver Fir both being stated by Selby to have attained these 

 magnificent proportions. The age attained by some Coniferse is no less astounding ; a 

 Taxodium, 117 feet in circumference, being inferred by De CandoUe to exceed 5150 

 years in age, the Sequoia 4000, the Yew and Cypress about 2000, and Pines, Firs, 

 Larches, and Cedars 300 to 500 years. 



The economic value of the Coniferae surpasses that of all other forest trees together, 



