Manual de Plantas de Costa Rica 109 
the Pacific coast), from near Cerro Chato in the northwest to the Montes del Aguacate in 
the southeast (see the section Physical geography in the chapter on The physical envi- 
ronment). The highest point is Cerro Los Amigos (1842 m), in the Monteverde Reserve. 
The vegetation of this cordillera is one of the more well studied and documented in 
the country (see Gomez-Laurito & Ortiz, 1996; Haber, 1991, 2000a; Haber et al., 
2000). Furthermore, a broad and detailed analysis of the flora (diversity, seasonality, 
biogeography), principally of the Monteverde region, provides sufficient information 
to get a good idea of the prevailing patterns (Haber, 2000a). Therefore, in this section 
we will enter into little detail. 
Generally speaking, the Cordillera de Tilaran is wetter than the Cordillera de Gua- 
nacaste, as is most graphically demonstrated by its greater area of rain forest (Tosi, 
1969). The elevational band of 700—1500 m on the Pacific slope is where one finds spe- 
cies of seasonal climates (Haber, 2000a), here shared primarily with adjacent moist 
forests at lower elevations, but also including species specific to this area. Microcli- 
matic and special edaphic conditions exist here that create sub-xeric conditions. In ref- 
erence to such conditions, Haber (2000a) cited various elements of dry, rocky cliffs, 
such as Echeveria australis, Euphorbia schlechtendalii, Furcraea cabuya, Pitcairnia 
heterophylla, P. maidifolia, and Plumeria rubra. 
A major component of the vegetation of the Cordillera de Tilaran comprises what 
is known as cloud forest. As reported by Haber (2000a), this forest type extends from 
1500 m on the Pacific side over the divide and down to 1300—1400 m on the Caribbean 
side, and has an annual precipitation of 2500-3500 mm. Haber also indicated that the 
highest diversity of plants in this cordillera is in the cloud forest. Some of the taxa most 
frequent, diverse, or abundant in (and therefore typical of) these forests are Alnus, Alza- 
tea, Araliaceae, Brunellia, Cyathea, Drimys, Ericaceae, Gunnera insignis, Hedyosmum, 
Ilex, Lauraceae, Magnolia, Melastomataceae, Meliosma, Morella, Myrsinaceae, Or- 
chidaceae, Quercus, Rubiaceae, Saurauia, Symplocos, Ticodendron, Ulmus, Viola stip- 
ularis, and Weinmannia. Some of these taxa are absent from the Cordillera de Guana- 
caste, or apparently quite rare there. 
The species diversity of these montane forests is due to a great extent to their high 
diversity of orchids and ferns; at Monteverde, orchids alone may make up more than 
19% of the total flora (Haber, 2000a). Tree ferns are particularly conspicuous indica- 
tors of cloud forest because of their affinity for areas of high humidity. According to a 
study of distribution along an altitudinal gradient (1535-1670 m) at Monteverde, tree 
ferns are most abundant in lower montane wet forest (> 1535 m); their diversity de- 
creases significantly with elevation, while abundance increases slightly (Lee et al., 
1988). Epiphytes (also with many species of orchids and ferns) form an important struc- 
tural component of these forests; they are most abundant in the cloud forest, and ac- 
count for 29% of the total 3021 species in the Monteverde flora (Haber, 2000a). Along 
the Continental Divide, in the water-laden, windswept elfin forests (a particular kind of 
cloud forest), one typically finds species such as Ardisia calycosa, Cosmibuena vale- 
