670 Part IV. Chapter 6. 
reached only by way of the rivers. Owing to the mountainous character of 
the country, over half of its area lies between goo and 2,100 meters above the 
sea and is almost wholly covered with virgin forest. This forest here and 
there ascends still higher, reaching the upper limit of the oak region about 
2,700 meters above the sea. 
The forest in the canal territory is of mixed growth, though the under- 
growth contains a large element of low-growing species. The larger trees are 
Ceiba pentandra (= Eriodendron anfractuosum), Hura crepitans, Cedrela, 
Erythrina and a few others. As one gets further into the forest, Castilloa 
becomes quite common. Although there are few features to differentiate this 
 territory botanically from other places in the same latitude, yet aroids and other 
climbing species are especially abundant'). As epiphytes growing upon the 
trees of this forest can be mentionned Zpidendrum rigidum, E. ciliare, E. 
radicans, E. piliferum, ÖOdontoglossum Schlieperianum, Comparettia falcata, 
Peperomia tenerrima and Polypodium Friedrichsthalianum. 
Nowhere is the vegetation of these tropic forests more luxuriant than on 
the banks of the rivers. Wild fig-trees form great bowers over the streams, 
evergreen Pithecolobiums emit a fine perfume, bamboos display their feathery 
tops and groves of the vegetable-ivory palm are at places conspicuous. 
Many plants and orders of the lowlands begin to disappear between 2,000 
and 3,500 feet in Panama; while tree ferns, grasses and showy orchids are 
conspicuous elements of the flora. The monocotyledonous undergrowth, the 
alms, cyclanthaceous plants, aroids and the genus Heliconia decrease con- 
siderably, while epiphytal orchids abound in the greatest variety. - The Ver- 
benaceae, Piperaceae, Papilionaceae, Compositae are as strongly represented 
as in the lower levels; while various Melastomaceae, Lauraceae, Tiliaceae, 
Clusiaceae, Apocynaceae and Vacciniaceae are peculiar a 
Oak Forest Formation. At about 7,000 feet on Volcan de los Vatos 
Costa Rica, oaks predominate and Podocarpus taxifolia, P. salicifolia, Drimys 
Winteri, Weinmannia sp. occur. The sides of Volcan de Barba at 6,000 to 
9,000 feet are covered with magnificent forests, consisting of oaks, Cedrela 
odorata, Eugenia lepidota, and laurels. The oaks are abundant above 7,000 feet. 
Here occur Ouercus virens (= O0. virginiana — O. retusa), O. costaricensts, 
Q. granulata;, species which become stunted at the summit of the volcano 
at 10,000 feet. 
Towards the upper limits of the tropie forest, below the oak forest in Costa Rica, such 
palms as Chamaedorea, Geonoma, Euterpe longepetiolata, Bactris (Guilielma) utilis and Carludo- 
vica microphylla are seen in great abundance, mixed with such tree-ferns as Alsophila pruinata, 
Hemitelia horrida, H. grandifolia, etc, — The slopes of Volcan de Cartago or Irazu (11,500 feet) 
above 7,000 feet also possess the forest of oaks, where in addition to the oaks mentioned above 
grows Quereus eitrifolia. The undergrowth consists of Cavendishia veraguensis, Siphocampylus 
Gutierrezii, Centropogon costaricanus, Myrtus Oerstedii, Hedyosmum calloso-serratum, Viburnum 
ı) CowELL: Explorations in Panama: see Bibliography p. 82. 
2) Hemsev: Loc. eit. p. 166. 
