Manual de Plantas de Costa Rica 225 
nari, Pterozonium, Stephanopodium, Tachia, Tapura, and Williamodendron are (or were) 
disjunct from Colombia or further south. Several genera are notable for being disjunct 
from at least as far north as Belize, e.g., Amelanchier, Bouvardia, Chiangiodendron, 
Deherainia, Hintonia, Nyssa, Oecopetalum, Recchia, and Tetranema. Except for the 
one species (N. talamancana) endemic to the Costa Rican and Panamanian Talaman- 
cas, Nyssa is otherwise known only from northern Mexico, the southeastern United States, 
and Southeast Asia. A few families (Canellaceae, Lepidobotryaceae) and genera 
(Apoplanesia, Bakeridesia, Crassula, Dacryodes, Pennellia, Rochefortia) are remark- 
able for their disjunct distributions both far to the north (or east) and far to the south. 
These few examples, taken only from recent discoveries, mirror the complex ori- 
gins of the total flora (see Origin of the flora, in the chapter on Vegetation). Costa Rica’s 
oft-emphasized great biodiversity (even by the standards of tropical forests) must cer- 
tainly be due not only to its diverse topography, climate, and soils, but also to its com- 
plex history and origin. For further discussion and bibliography on factors theorized to 
contribute to species richness in general, see Rosenzweig (1995), and for Costa Rica 
specifically, Burger (1985, 1995). 
Detailed account by regions 
The following discussions of the localities where recent Costa Rican plant discoveries 
have been made, more or less with reference to the floristic or botanical regions already 
mentioned, help indicate the floristic diversity and origin of each of the regions. The 
species listed serve to complement and reiterate the proposed characterizations of these 
regions (see chapter on Vegetation). Those marked with an asterisk (*) are endemic to 
Costa Rica. 
Major mountain ranges (cordilleras) 
A large part (60% or more) of the additions to the flora over the last 15 years has re- 
sulted from exploration of the cordilleras, where the majority of endemic species are 
also concentrated. The Cordilleras de Guanacaste, de Tilaran, and de Talamanca, espe- 
cially, have been studied more or less continuously, with the Cordillera de Talamanca 
contributing the greatest number of new records. 
The new species or new country records from the Cordillera de Guanacaste include 
Allenanthus erythrocarpus, Cryptocarya sp., Dussia atropurpurea*, Elaeodendron xy- 
locarpum, Freziera forerorum, Inga herrerae*, Licania riverae*, Lonchocarpus cal- 
caratus, L. retiferus, Maxillaria mombachoensis, Oncidium parviflorum, Pavonia 
malacophylla, Peperomia angustata, Platymiscium yucatanum, Platystele obtecta*, 
Rochefortia lundellii, Senna racemosa, Verbesina guatemalensis, and Werauhia vul- 
canicola. 
Relatively intensive recent floristic work in the Cordillera de Tilaran, mostly due to 
the efforts of William Haber and associates in the Monteverde region, has resulted in a 
