BOTANICAL GEOGRAPHY. 441 



shrubs, and by this connected green and fresh vegetation, the Sierra Morena 

 differs from all other mountains of Andalusia, which only contain isolated 

 spots of wood, and a low, barren " montebaxo." Geologically considered, 

 the principal rocks of the Sierra Morena consist of sandstone, which, in the 

 form of grauwacke, forms the greater part of the mountain-chain, occurring 

 from 4 to 6 geog. miles broad, in gently-rounded mountains and undulating 

 summits, alternating at Almaden with clay slate, in the province of Huelva 

 with gneiss, and southwards, near the low plain of the Guadalquiver, inclosed 

 by other sandstone formations. The central portion of the mountains is 

 interrupted by the immense granitic formation of Cordova, which, in the 

 form of an elevated plain, inclines from Hinojosa towards the north, and 

 becomes connected there with white quartzose rocks, which, between Almaden 

 and Fuencaliente, appear to form the highest chain of the whole Sierra. 

 In the opinion of the traveller, the character of the vegetation is associated 

 with these geological variations, which are lithologically unimportant. The 

 predominating shrub on the grauwacke, as far as Portugal, is Cistus ladini- 

 ferm, which extends over the Sierra Morena for a length of more than 50 geog. 

 miles, and " frequently covers whole square leagues exclusively." Next to 

 this, the most common are Phillyrea angustifolia, Rosmarinus, and a Heli- 

 antliemum. The forests on the grauwacke consist of evergreen oaks, of 

 Quercus Ilex, Ballota, and Suber, but the first is mostly only a shrub ; the 

 dry, arid, but densely-populated granite plateau is very sterile, but still pos- 

 sesses extensive woods of Quercus Ilex and Ballota, only a dwarf growth, 

 however, of Quercus Ilex, mixed with Cistus ladaniferus, PMllyrea angusti- 

 folia, and Arbutus unedo. The southern sandstone chains are furnished with 

 an extremely luxuriant and varied " montebaxo," which, near the city of 

 Cordova, alternates with woods of pines and cork-oaks. The quartzose rocks 

 of Mancha are also covered by a "montebaxo" abounding in forms, among 

 the shrubs of which Cistus populifolim is distinguished. Finally, in Huelva, 

 Portuguese forms are associated with the other shrubs, as Genista tridentata, 

 Ulex genistoides, and with these Erica umbellata, Teucrium fruticans, and 

 Helianthemum halimifolium. Unfortunately, Willkomm has not made us ac- 

 acquainted with the vernal vegetation of the Sierra Morena, which would be 

 the most interesting. But the dryness of the summer commences here in 

 July, and from that time until the autumn no more flowering plants are met 

 with. Different kinds of bulbous plants appear very uniformly distributed 

 in the autumn, as Scilla maritima, Scilla autumnalis, Leucojum autumnale, 

 Merendera Bulbocodium, &c. 



Boissier's large work upon the southern border of 

 Granada and the Sierra Nevada forms the most valuable 

 contribution to botanical geography which has been made 

 during the past year (Voyage botanique dans le Midi de 

 de 1'Espagne, t. i. Narration and Geographic botanique, 



