Manual de Plantas de Costa Rica 147 
rothyrium oblongum, Quassia amara, Sci- 
adocephala dressleri, and Styphnolobium 
sp. nov. Quassia amara is sometimes com- 
mon in the understory and middle layers of 
these forests. Some of these same elements 
are among those that we consider part of the 
characteristic flora of the Osa Peninsula, to- 
ward the southwest on the other side of the 
Talamancan mountain range, demonstrating 
a floristic as well as a climatic relationship 
between these two areas. 
Continuing on toward Panama to the ex- 
treme southeast of Baja Talamanca, wherein 
lie sites such as Manzanillo, Gandoca, Bri- 
bri, and Bratsi, slightly drier conditions pre- 
vail. This part of the subregion was mapped 
and classified as tropical moist forest by Tosi 
(1969) and Herrera & Gomez P. (1993). 
Even though these authors pointed out that 
there are no rain-free months in this area, 
some seasonality is indicated by the pres- 
ence of certain species typical of the very seasonal Pacific slope, e.g., Adelia triloba, 
Aphelandra aurantiaca, Brickellia diffusa, Brosimum alicastrum, Bunchosia macro- 
phylla, Cayaponia racemosa, Cynometra hemitomophylla, Esenbeckia pentaphylla, 
Forchhammeria trifoliata, Garcinia macrophylla, Guatteria amplifolia, Hiraea recli- 
Swamp forest, Gandoca-Manzanillo 
National Wildlife Refuge (1999) 
nata, Ixora floribunda, I. nicaraguensis, Miconia lacera, Nectandra hihua, N. um- 
brosa, Notopleura capitata, Olmedia aspera, Omphalea diandra, Osa pulchra, Ryania 
speciosa, Tabernaemontana alba, Trattinnickia aspera, and Virola multiflora. 
A few species that are quite rare country-wide, but more or less common in this re- 
gion, are Abarema barbouriana, Agouticarpa williamsii, Alibertia utleyorum, Anaxa- 
gorea panamensis, Capparis filipes, C. heydeana, Chloroleucon eurycyclum, Duguetia 
panamensis, Guazuma invira, Herpetacanthus stenophyllus, Inga jefensis, Lunania 
parviflora, Manilkara spectabilis, Pentagonia costaricensis, P. hirsuta, Psychotria 
limonensis, P. sixaolensis, Sabal mauritiiformis, Stenanona panamensis, Unonopsis 
storkii, and Zygia confusa. 
The vegetation from the Llanura de Tortuguero to Baja Talamanca fits within 
Gomez P.’s (1982) Amazonian category, which he later (G6mez P., 1986) called the 
Costa Rican center; it comprises a mixture of elements from the northwestern Pacific 
slopes of South America and cis-Andean Amazonia along with species from Meso- 
america (Mexico—Panama). Some of the clearly Amazonian elements (especially those 
from the Atlantic coast of northern South America) that reach here are Amanoa guia- 
