668 Part IV. Chapter 6. 
The Volcan Santa Maria (12,457 feet) in the Department of Quezaltenango 
is likewise clothed with forest vegetation which reaches the summit. The 
eruption of 1902 completely destroyed the vegetation on the south and south- 
west side where a new crater of immense size was formed. 
Above 2,700 meters, the trees of the tropie rain forest appear no more, but the forest forming 
a Mixed Mountain Forest Formation consists of broad-leaved and coniferous trees, such 
as oaks, alders, pines, spruces and cypresses. The undergrowth consists of species of Vaccinium 
and shrubs of myrtle form. Many stems in this forest are decidedly mossy with a growth of 
epiphytic mosses. Mountain meadows occasionally interrupt the continuity of this forest forma- 
tion as at Chancol and Rosario (3,100 meters). 
Above the tree limit, as on Tacana (13,364 feet = 4073 m) and Tajumulco (13,814 feet) the 
botanist finds a Treeless Grassland Formation, grassy stretches characterized by low 
flowering plants mostly found at the top of precipices, the sides of waterfalls, or wherever the 
sun can reach the ground. At places where large wet surfaces of lava have no covering of soil, 
they are carpeted over with thick beds of mosses and ferns. The upper limit of flowering 
plants or the border of the eternal snows is never reached on any of the volcanoes of Central 
America. 'The summits of Atitlan and Volcan de Fuego are without vegetation, while the peak 
of Pacaya is covered by a sparse flora. Between 3,700 and 3,800 m is the upper limit of 
the coniferous forests. Single twisted specimens of sterile pines ascend on the moist southeast 
declivities of Volcan Tacana and Tajumulco to 3,980 meters, while the tree limit is much: less 
elevated on the north and northwest slopes of the mountains, 
4. Costa Rican Region. 
This southern floral region of the Central American Tropic Sec- 
tion, comprising southern Nicaragua, Costa Rica and Panama, exhibits a close 
relationship with the South American Tropic flora. The composition of 
the Panama flora as far as investigated is decidediy South American. For 
example, according to HEMSLEY ‘), the Dilleniaceae and Anonaceae thin out 
northward. The eastern South American order Lecytindaceae is represented 
by four genera and seven species, one of which reaches Nicaragua, its northern 
limit. Podocarpus with two species (P. taxifolia and P. salicifolia) replaces 
Pinus in the mountains of Costa Rica. The southern limits of such northern 
types as Liguidambar, Sabiaceae and Fuglandaceae are reached in Costa Rica. 
Arbutus and Arctostaphylos are replaced by South American genera of the 
Vacciniaceae in the mountains, 
The Nicaraguan Hylaea of PoLAKOwskY ?) which includes the forests of 
the basin of the Rio San Juan and the southern shores of Lake Nica- 
ragua can be taken, as the boundary country separating the cis-equatorial 
flora from that of Guatemala and Mexico. It may be said to represent the 
line which delimits the North American flora proper from that of South 
America. Therefore, we have here to consider this region only as an anneX 
to the foregoing regions. 
ı) HEmsLev, W. B.: Biologia Centrali-Americana IV: 313. 
2) POLAKOwskv, H.: Pflanzenwelt von Co : nn R Ropt.: 
t : » Cfr. RIDGwAY, 
Condor VII: 151— 160, sta Rica: see Bibliogr. p. 85; Cfr. Rın , 
