The raltionship between relief, climate and vegetation, is evident as is ots influence in certain socioeconomic sectors, in agraculture and in tourism. A nation's vegetation is a reliable reflexion of climatic diversity as can bee seen in the distinctive landscapeds of the two Spains: green Spain with its lush, extensive decidious forests and its rich grassy plains, and Mediterranean Spain, with its xerophytic, untilled scrubland together with sparse woodland that has adapted to the summer dryness. Its varied landscapes and richness of flora (over 8,000 species) constitute another type of crossroads, in which plants from all over Europe encounter and mingle with vegetation from the North of Africa. Thus the European beech may grow alongside the Mediterranean oak, the Aleppo pine, the African palm and even the Australian eucalyptus.

This botanical crossroads is characterized by certain well-defined areas which correspond in good measure to the great Spanish climatic types. Wet Spain is dominated by forest, in which such species as the beech and the oak abound, as they thrive in damp, maritime regions, with their flat, moist leaved that drop off in the colder winter months. This frest mass is accompanied by a rich and varied undergrowth dominated by ferns, gorse and heather. The rugged relief of the terrain and the altitude affect the occurence of the various types of vegetation; for example, on the dhady foothills of the mountain ranges are oaks groves while holm oaks and other similar trees tend to thrive out in the open; higher up, the terrain is dominated by beech and chestnut, according to the soil type while reforestation has added various species or spruces; even higher one finds alpine meadows and scrub.

The dry Spain is further divided into two distinct vegetation groups, according to its peculiar temperatures and aridity, which correspond to the Meseta and the Iberian depression on the one hand and to the Mediterranean Spain per se on the other. These two groups have in common their adaptability to aridity, which has given place to a combination of wood-land and scrub that can thrive with very little moisture. Nevertheless, and in spite of the deterioration, produced by man, a typical forest of holm oaks and cork trees survives on the Meseta, although the latter generally prefer the more silic soils and the shady groves of the south and west of the region, which strech out into western Andalusia.

In the dryer areas, such as La Mancha, Extremadura and particularly the Ebro valley the holm oak is replaced by sparse, very dry, thorny scrub. In the wetter more silic regions (Leon, Extremadura), it is the maquis; in the dryer, calcareous soils of La Mancha and La Alcarria, it is the garriba; and finally, yhe steppe, both man-made and natural, which is becoming increasingly affected by both erosioin and desertification, above all in western Andalusia and the Levante region.

In the Mediterranean coastal zones one finds a more complex botanical mixture. On the coast itself, the holm oak-cork forests are interspersed with a coniferous mass dominated by the Aleppo pine, which, upon reaching higher altitudes, is replaced by other type of conifers more suitable to mountainous regions, such as the larch and the Scotch pine. Together with these, and according to the area, it is possible to find beech and oak, in the case of the central sierras of the Meseta, or oak and chestnut in the Sierra Nevada, or even the Spanish fir, a conifer of north African origin in the foothills of Ronda. In the higher altitudes, one finds a treeless type of landscape covered with xerophytic scrub that has adapted to the dry, cold temperatures typical of Mediterranean mountain regions. To the contrary, a type of desert withg very scant vegetation extends to the shores of the Mediterranean in the southeastern parts of Murcia and Andalusia. In this latter, several exotic species of plants are frequently found, such as the dwarf fan palm, the Indian prickly-pear and aloa plants. Occasionally a compact or a disperse palm grove will sprout if there is sufficient surface of subterranean water.