Dr. Polakowsky, in an interesting publication entitled “Flora of Costa Rica,” calls the forest region of the San Juan River, in view of its luxuriant character, “The Central American Hylæa,” and this name Professor Pittier applies also to the entire Atlantic region, attributing to it a distinctly South American character. The zone of the open forests and savannas, which has park-like features, is rarely found away from the Pacific side, where it forms a belt from sixteen to eighteen miles in width, interspersed with more densely forested river valleys, islands of higher and thicker virgin forests, isolated trees or groups of trees, sometimes also with _catingas_ and meadows flecked with shrubs and matorrales. The savannas and open forests spread to a considerable extent over Guanacaste, where they are a continuation of those of Rivas in Nicaragua; also over the plains of Terraba, especially in the region of Buenos Aires and Terraba; and over the coast-lands of Golfo Dulce. There are some small similar tracts near Alajuela, Turialba, Santa Clara and at some other points, as well as catingas and _paramos_ in the high mountain ridges of the south. The paramos are found on poor soil and have a vegetation more herbaceous than ligneous, which, when moist, takes on the character of turf. The trees of the savannas are generally of little height, excepting the _Enterolobium cyclocarpum_ (the guanacaste), the pochote and ceiba. The grass lands are almost wholly composed of _Gramineæ_ and _Cyperaceæ_, especially in the savannas of Guanacaste. The most characteristic plants are _Digitaria marginata_ and _Paspalum notatum_, besides species of _Setaria_, _Panicum_, _Eragrostis_, _Andropogon_, _Isolepis_, _Cyperus_, _Rhynchospora_ and _Scleria_, as well as of ferns (_Pteris aquilina_) and _Schizæa occidentalis_. Other abundant plants in the open forests and savannas are _Compositæ_ (_Zemenia_, _Pectis_, _Spilanthes_); _Rubiaceæ_ (_Spermacoce_); _Polygalaceæ_; _Iridaceæ_; _Moraceæ_ (_Maclura_, _Ficus_); _Melastomaceæ_ (_Miconia_, _Clidemia_, _Conostegia_, _Leandra_); _Cyperaceæ_; _Convolvulaceæ_; _Euphorbiaceæ_; _Bombacaceæ_; _Sauvagesia_. Further, _Myrtaceæ_ (_Psidium_, _Alibertia edulis_); _Curatella americana_ (chamico); _Roupala_ (danto hedliondo); _Byrsonima crassifolia_ (nance); _Miconia argentea DC._ (santa maria); guacimo macho (_Luhea_), guacimo de ternero (_Guazuma ulmifolia_); burio (_Bombax apeiba_); ñambar (_Cocobola_); _Davilla lucida_; _Duranta Plumieri_; _Proteaceæ_; and _Acacia scleroxyla Lonchocarpus atropurpureus,_ _Dalbergia_ and many other _Leguminosæ_, especially _Mimosa pudica_, which gives large tracts in many places a special character, and still more so as, being often very abundant and the plants tangled together, a general movement all around is caused when one is touched.