Manual de Plantas de Costa Rica 111 
rioi, Dendropanax latilobus, Drimys grana- 
densis, Myrsine coriacea, Schefflera rodri- 
guesiana, and Zanthoxylum melanostictum. 
According to Haber’s (2000a) analysis 
of data from 20,000 specimens from the 
Monteverde area, the forests above 1200 m 
—accounting for 57% of the total 3021 spe- 
cies of the area— appear to be more diverse 
than those in the 700—1200 m band on the 
Caribbean slope, but that result may be a re- 
flection of fewer collections from the Carib- 
bean slope. Haber’s | ha plot data on trees 
reveal 104 species in 39 families at 750 m 
(the Pefias Blancas site) and 115 species in 
36 families at 1150 m (the San Gerardo site). 
At the Alberto Manuel Brenes Biologi- 
cal Reserve in San Ramon, on the Caribbean 
slope of the Cordillera de Tilaran at 550- 
1650 m elevation, totals of 1008 species, 
440 genera, and 130 families have been re- Monteverde (©1993 Steven Ingram) 
corded (Gémez-Laurito & Ortiz, 1996). A 
1 ha plot at this site, at 910-950 m elevation, registered 94 species of trees in 40 fam- 
ilies, with the most frequent (in order of abundance) being: /riartea deltoidea, Plinia 
salticola, “Guarea glabra,” Inga leonis, I. barbourii, Warszewiczia uxpanapensis, 
Sloanea faginea, Cupania macrophylla, Calatola costaricensis, Lonchocarpus hepta- 
phyllus, Conostegia micrantha, and Pseudolmedia oxyphyllaria (Wattenberg et al., 
1996). The authors of this latter work also indicated that 15.6% of the total 519 stems 
counted in the plot were tree ferns, a high abundance for that group of plants. They also 
found that some species more typical of wet lowland forests also occurred up to this 
elevation, e.g., Allophylus psilospermus, Chimarrhis parviflora, Coccoloba tuerckhei- 
mii, Hernandia stenura, Iriartea deltoidea, Licania hypoleuca, Naucleopsis naga, and 
Otoba novogranatensis. Numerous montane species are also found here, such as Alfaroa 
costaricensis, Licania kallunkiae, Perrottetia longistylis, Ruagea glabra, and Weinman- 
nia pinnata. These findings are in agreement with the observations of Boyle (1996), 
whose comparison of changes along altitudinal transects in montane forests of Mexico, 
Costa Rica, and Ecuador showed this transition at approximately 1000 m. 
Once again using the family Rutaceae for comparison, we see that in the Cordillera 
de Tilaran 43% of the total 16 genera known for the country have been found, with 36% 
of the total 33 species, a lower diversity than for the Cordillera de Guanacaste. Some 
species that also occur in the Guanacaste range are much less abundant here, e.g., Pel- 
tostigma guatemalense and Pilocarpus racemosus, while other such species, such as 
