Manual de Plantas de Costa Rica 207 
focused almost entirely on Guanacaste, as though the central Pacific lowlands and the 
Osa Peninsula did not exist. Botanically speaking, they did not; exploration of the Osa 
Peninsula did not really begin until the late 1960s, and only scant collections from the 
central Pacific lowlands might have been available to Standley. Fortunately, the Manual 
project made a concerted effort to sample the Osa Peninsula; essentially within the time 
since the beginning of the project, we have witnessed the clearing of much of the penin- 
sula’s unprotected parts. Our first trips onto the neck of the peninsula in the mid-1980s 
were awe-inspiring and botanically treasure-filled journeys along a tunnel-like dirt road 
into dense and tall tropical wet forest. Now this same road is paved, and with only 
patches (still treasure-filled) of forest dotting the pastures that allow panoramic views of 
Golfo Dulce to the south, the Sierpe swamp to the north, and the Talamanca cordillera 
as a backdrop. We also now have considerable collections from the central Pacific low- 
lands, because of concentrated efforts in La Cangreja (Acosta, 1998) and Carara (Jimé- 
nez M. & Grayum, 2003) National Parks. These areas of the Pacific lowlands, while still 
influenced by a definite dry season, receive far more rainfall than the Guanacaste low- 
lands, and some even exceed parts of the Caribbean lowlands for yearly totals. INBio’s 
database presently records 2334 species of vascular plants from the Osa Peninsula, 
based on 11,319 collections, so current data should show much more floristic similarity 
between the Pacific and Caribbean lowlands than Standley’s observations suggested. 
Accustomed to thinking that the very wet tropics are more diverse than the dry trop- 
ics, and having in mind the generalization of a wetter Caribbean vs. drier Pacific slope 
in Costa Rica, we were somewhat surprised that the database showed a total of 6454 
species of vascular plants (ca. 52,000 collections) from the Caribbean slope and 7348 
species (ca. 67,000 collections) from the Pacific slope. If these estimates are indicative 
of real differences between the two slopes, the greater heterogeneity of the Pacific 
slope—at least in rainfall, if not also in soil types—might easily explain the greater 
number of species. Less interestingly, the differences shown by these numbers may 
simply reflect the higher density of collecting from the Pacific slope. 
As mentioned at the end of the section on Botanical exploration and floristics in 
Costa Rica, in the History chapter, the vast majority of collection records on the INBio 
database are (partly by design) from below 1500 m elevation, where it was expected 
that the greatest numbers of species and therefore new discoveries lay; 80% of the ca. 
120,000 numbers are from that broad, low to mid-elevational range (see Fig. 4, p. 209). 
However, it is also obvious, from a glance at the topographic map of the country (see 
map on front endpapers), that a much greater amount of surface area in the country lies 
below 1500 m than above. Even just by chance, one would expect most collections to 
be from the lower band. With that in mind, the division of the lower elevations (and not 
the upper) into their Caribbean and Pacific slope components makes sense not only for 
their more marked climatological differences, but also because the four resulting bands 
are somewhat more comparable in surface area. 
Indeed, it is interesting to note that, even though the greatest number of collections 
