Among the epiphytes and parasites may be mentioned small ferns, _Peperomia_, _Epidendrum_, _Loranthus_, _Aroideæ_, _Tillandsia_ and other _Bromeliaceæ_, mosses, lichens, etc. Professor Pittier attributes to this flora of the Pacific slope a more northern origin. During the dry season the vegetation of the savannas almost disappears, the greater part of the trees and bushes shed their leaves and herbs become dry and brittle. Only along the rivers is some freshness observable. Toward the border of Nicaragua cacti appear, mostly species of _Cereus_, _Opuntia_, _Phypsalis_ and _Mammilaria_. Professor Pittier also mentions an oak forest of _Quercus citrifolia_ between Liberia and the Rio de los Ahogados, at a height of about one hundred meters above the sea. The peninsula of Nicoya is noted for a large lumber industry among its different cedars (_Cedro dulce_, _C. amargo_, _C. real_, etc.), mora and other trees. Towards the upper limits of the Atlantic tropical forests, below the oak region, _Chamædorea_, _Geonoma_, _Bactris_, _Euterpe longepetiolata_ and other palms of the same groups, as well as _Gulielma utilis_ (the pijivalle palm) and _Carludovica microphylla_ are seen in great abundance, mixed with tree ferns like _Alsophylla pruinata_, _Hemitelia horrida_, _Hemitelia grandifolia_, etc. Higher up appears the region of oaks, principally _Quercus retusa_, _Quercus granulata_, _Quercus citrifolia_ and _Quercus costaricensis_, with _Buddleia alpina_, _Rubus_, _Lupinus_, etc. Here is also the region of the common potato. This oak region slopes gradually down from east to west. The vegetation on the summits of the high mountains of Costa Rica is of a marked subalpine character, having a great number of northern genera, as _Vaccinium_, _Pernettya_, _Alchemilla_, _Cardamine_, _Calceolaria_, _Spiræa_, etc. Certain types of vegetation are often more due to the sterile nature of the soil than to elevation. Although a northern flora is frequent on the high terraces of San José and Cartago, that character is not general because of the introduction of cultivated tropical and other plants peculiar to Costa Rica. On the southern high mountains two species of _Podocarpus_ (_P. taxifolia_ and _P. salicifolia_), one of _Alnus_ (_Alnus Mirbelii Spach._) and one of _Weinmannia_ occur quite generally among the oak forests. Other distinct floral groups are represented by the vegetation along roads and fences, on potreros, in cultivated regions and along river shores. The latter especially are rich in herbaceous plants, grasses, bushes and woods of _Bignoniaceæ_, _Myrtaceæ_, _Euphorbiaceæ_, _Mimoseæ_, etc. The potreros are characterized by _Tagetes_, _Sida_, _Hyptis, olanum_, _Salvia_, _Mimosa pudica_ and _M. sensitiva_, etc. Along fences there grow nearly everywhere _Erythrina corallodendron_, _Yucca aloifolia_, _Bromelia pinguin_, _Agave americana_, _Cereus_, _Spondias_, _Bursera_, _Cestrum_, etc.